Insulin resistance: a metabolic pathway to chronic liver disease

Molecular and Pathological Events Involved in the Pathogenesis of Diabetes-Associated Nonalcoholic Fatty Liver Disease

Diabetes mellitus is a rising epidemic in most part of the world and is often associated with multiple organ disorders such as kidney, liver, and cardiovascular diseases. Liver is a major metabolic hub, and the metabolic disorders associated with diabetes result in liver dysfunctions culminating in spectrum of liver diseases such as fatty liver disorders, cirrhosis, and hepatocellular carcinoma. The intervention strategies to prevent diabetes-associated liver injury require an overall understanding of the key factors and molecular pathways which can be strategically targeted. The present review focuses on some of the key aspects of fatty acid metabolism, fetuin-A regulation, inflammatory pathways, and genetic factors associated with insulin resistance, dyslipidemia, hyperglycemia, oxidative stress, and so on involved in the nexus between diabetes and liver injury. Further recent interventions, pharmacological target, and newer therapeutic agents are discussed briefly for the better clinical management of diabetes-associated hepatic disorders.

Plasma ApoE elevations are associated with NAFLD: The PREVEND Study

Non-alcoholic fatty liver disease (NAFLD) is featured by increased plasma very low density lipoproteins (VLDL). The extent to which plasma apolipoprotein E (ApoE) levels are elevated in NAFLD is unclear. We determined whether plasma ApoE is elevated in subjects with suspected NAFLD. Plasma ApoE and genotypes were determined in 6,762 participants of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) cohort. A Fatty Liver Index (FLI) ≥ 60 was used as a proxy of NAFLD. A total of 1,834 participants had a FLI ≥ 60, which coincided with increased triglycerides, non-HDL cholesterol, ApoB and ApoE (all P<0.001). In multivariable linear regression analysis, plasma ApoE levels were positively associated with an elevated FLI when taking account of ApoE genotypes and other clinical and laboratory covariates (fully adjusted model: β = 0.201, P<0.001). Stratified analysis for ApoE genotypes (ApoE ε3ε3 homozygotes, ApoE ε2 carriers, and ApoE ε3ε4 and ε4ε4 carriers combined), also showed positive associations of plasma ApoE levels with an elevated FLI in each group (all P<0.001). In conclusion, it is suggested that NAFLD is characterized by increased plasma ApoE levels, even when taking account of the various ApoE genotypes. Increased plasma ApoE may contribute to altered VLDL metabolism and to increased atherosclerosis susceptibility in NAFLD.

Natural course of fatty liver in 36,195 South Korean adults

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver disease, and yet the natural course remains unclear. Study population included 36,195 individuals who participated in a health-screening program and diagnosed with fatty liver by abdominal ultrasound. Participants were provided written information regarding fatty liver and advised to make lifestyle changes. Ultrasound was repeated after at least 6 months. After a mean follow up of 4.9 years (±3.4), 19.6% resolved their fatty liver. Individuals who resolved were more likely female (22.9% vs. 12.3%), thinner (body mass index [BMI], 25.2 ± 2.7 vs. 26 ± 2.7), and with lower HOMA-IR (1.4 vs. 1.7) (P .70.001). Decrease in BMI predicted resolution of fatty liver with 42% of those in the top quartile of BMI decline resolving compared with 5.7% in the lowest quartile (odds ratio [OR] (95% confidence interval [CI]) 15.65 (14.13–17.34), P < 0.001)). Baseline HOMA-IR also predicted resolution with those in the top quartile (most insulin resistant) being least likely to resolve (12%) vs. those in the lowest quartile (25%) (OR 0.36 [0.31–0.42], P < 0.001). Fatty liver disease is persistent. Individuals with higher degree of insulin resistance are also the most likely to have persistent steatosis at follow up.

Association of adipokines with hepatic steatosis and fibrosis in chronic hepatitis B patients on long-term nucleoside analogue

BACKGROUND & AIMS

It is unknown how concomitant hepatic steatosis affects disease progression in chronic hepatitis B (CHB). Adipokines such as fibroblast growth factor 21 (FGF21) and adipocyte fatty acid-binding protein (AFABP) have been associated with non-alcoholic fatty liver disease. We determined the significance of these metabolic markers in CHB-related liver injury.

METHODS

We recruited CHB patients on antiviral treatment for transient elastography assessment to determine liver stiffness (advanced fibrosis/cirrhosis, F3/F4, defined by EASL-ALEH criteria) and controlled attenuation parameter (hepatic steatosis, defined as ≥ 248 dB/m). Plasma FGF-21, AFABP and adiponectin levels were measured.

RESULTS

A total of 415 patients [mean age 59.6 years, 71.6% male, median treatment duration 6.2 years] were recruited. Patients with F3/F4 (N = 151) had lower FGF-21 (11.7 vs 13.6 pg/mL, P = 0.055), higher AFABP (126.8 vs 84.1 pg/mL, P < 0.001) and HOMA-IR (7.1 vs 5.1, P = 0.004) levels compared to those without F3/F4 (N = 264). Multivariate analysis showed that FGF-21 level was associated with hepatic steatosis (OR 1.005, 95% CI 1.001-1.009) and F3/F4 (OR 0.993, 95% CI 0.989-0.998), while AFABP level (OR 1.001, 95% CI 1-1.002), body mass index (BMI) (OR 1.107, 95% CI 1.037-1.182) and presence of diabetes mellitus (OR 2.059, 95% CI 1.206-3.516) were associated with F3/F4. With the combined presence of BMI ≥ 25 kg/m² , diabetes and AFABP > 105.9 pg/mL, the odds ratio for F3/F4 was 3.712 (95% CI 1.364-10.105, P = 0.010).

CONCLUSIONS

Low FGF-21 and high AFABP levels were associated with advanced fibrosis/cirrhosis in CHB patients on antiviral treatment. Plasma AFABP, together with other metabolic risk factors, may aid identification of patients lacking fibrosis improvement during antiviral treatment.

Serum fetuin-B level is an independent marker for nonalcoholic fatty liver disease in patients with type 2 diabetes

OBJECTIVE

Previous studies have assessed serum fetuin-B and its relation to nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) and as a link between them through inducing insulin resistance (IR). Therefore, we examined the potential of serum fetuin-B to be an independent marker for NAFLD in patients with T2DM.

PATIENTS AND METHODS

The study group consisted of 270 patients with T2DM. Clinical and laboratory features were evaluated. The NAFLD severity was graded by ultrasound into three subgroups: grade 0 (no fatty liver), grade 1 (mild fatty liver), and grade 2-3 (medium to severe fatty liver). Fetuin-B, retinol-binding protein-4, and adiponectin were measured.

RESULTS

Patients with grade 2-3 NAFLD had high fetuin-B levels in comparison with non-NAFLD group. Age and sex adjusted fetuin-B demonstrated positive correlations with triglycerides, γ-glutamyl transferase, fasting plasma glucose, 2-h postprandial plasma glucose, homeostasis model assessment of IR, fasting insulin, glycated hemoglobin, high-sensitivity C-reactive protein, and estimated glomerular filtration rate, but it had a negative correlation with serum creatinine. Adiponectin level was decreased with increasing NAFLD severity, but no difference was found in retinol-binding protein-4. The estimated odds ratio (OR) for the occurrence of grade 2-3 NAFLD was increased significantly with increasing levels of fetuin-B (OR: 3.92; 95% confidence interval: 2.14-8.32 vs. OR: 8.91; 95% confidence interval: 4.22-18.41). The OR of fetuin-B in the uppermost tertile group was still significant after controlling for homeostasis model assessment of IR, glycated hemoglobin, waist circumference, BMI, hepatic enzymes, high-density lipoprotein cholesterol, triglycerides, and high-sensitivity C-reactive protein.

CONCLUSIONS

Our study demonstrated that serum fetuin-B had an independent association with NAFLD in patients with T2DM.

Dietary Glycotoxins Impair Hepatic Lipidemic Profile in Diet-Induced Obese Rats Causing Hepatic Oxidative Stress and Insulin Resistance

Nonalcoholic fatty liver disease (NAFLD) is caused by excessive liver lipid accumulation, but insulin resistance is specifically associated with impaired lipid saturation, oxidation, and storage (esterification), besides increased de novo lipogenesis. We hypothesized that dietary glycotoxins could impair hepatic lipid metabolism in obesity contributing to lipotoxicity-driven insulin resistance and thus to the onset of nonalcoholic steatohepatitis (NASH). In diet-induced obese rats with methylglyoxal-induced glycation, magnetic resonance spectroscopy, mass spectrometry, and gas chromatography were used to assess liver composition in fatty acyl chains and phospholipids. High-fat diet-induced obesity increased liver lipid fraction and suppressed de novo lipogenesis but did not change fatty acid esterification and saturation or insulin sensitivity. Despite a similar increase in total lipid fraction when supplementing the high-fat diet with dietary glycotoxins, impairment in the suppression of de novo lipogenesis and decreased fatty acid unsaturation and esterification were observed. Moreover, glycotoxins also decreased polyunsaturated cardiolipins and caused oxidative stress, portal inflammation, and insulin resistance in high-fat diet-induced obese rats. Dietary glycated products do not change total lipid levels in the liver of obese rats but dramatically modify the lipidemic profile, leading to oxidative stress, hepatic lipotoxicity, and insulin resistance in obesity and thus contribute to the onset of NASH.

Adenovirus-mediated expression of SIK1 improves hepatic glucose and lipid metabolism in type 2 diabetes mellitus rats

Aim

In this study, we investigated the role and mechanism of Salt-induced kinase 1 (SIK1) in regulation of hepatic glucose and lipid metabolism in a high-fat food (HFD) and streptozocin (STZ)-induced type 2 diabetes mellitus (T2DM) rat model.

Methods

A diabetic rat model treated with HFD plus low-dose STZ was developed and was transduced to induce a high expression of SIK1 in vivo via a tail-vein injection of a recombinant adenoviral vector. The effects on hepatic glucogenetic and lipogenic gene expression, systemic metabolism and pathological changes were then determined.

Results

In T2DM rats, SIK1 expression was reduced in the liver. Overexpression of SIK1 improved hyperglycaemia, hyperlipidaemia and fatty liver, reduced the expression of cAMP-response element binding protein (CREB)-regulated transcription co-activator 2 (CRTC2), phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase), pS577 SIK1, sterol regulatory element binding-protein-1c (SREBP-1c) and its target genes, including acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), and increased the expression of SIK1, pT182 SIK1 and pS171 CRTC2 in diabetic rat livers with the suppression of gluconeogenesis and lipid deposition.

Conclusion

SIK1 plays a crucial role in the regulation of glucose and lipid metabolism in the livers of HFD/STZ-induced T2DM rats, where it suppresses hepatic gluconeogenesis and lipogenesis by regulating the SIK1/CRTC2 and SIK1/SREBP-1c signalling pathways. Strategies to activate SIK1 kinase in liver would likely have beneficial effects in patients with T2DM and nonalcoholic fatty liver disease (NAFLD).

Drug repurposing in alternative medicine: herbal digestive Sochehwan exerts multifaceted effects against metabolic syndrome

New drug development is a challenging process that requires high-risk, huge costs and long lead times. Therefore, drug repurposing is considered a strategic and economic way towards successful drug development. Sochehwan (SCH) is a herbal formula well known as a digestive aid in traditional oriental medicine, is referred to in classic medical texts, and is available as an over-the-counter drug for indications of digestive ailments. Interestingly, another medical text written in earlier age describes different indication of SCH yet to be examined. We conducted a series of investigations using maturated adipocytes, free fatty acid (FFA) induced hepatic steatosis model in vitro and high-fat diet (HFD) mice model in vivo. Exposure to SCH regulated expression of adipogenic genes and proteins, significantly inhibiting formation of lipid droplets in 3T3-L1 cells. Similarly, SCH treatment modulated proteins related with energy metabolism decreasing lipid accumulation in FFA induced HepG2 cells. Furthermore, HFD-fed c57BL/6 J mice supplemented with SCH exhibited significant changes in serum glucose and lipid profiles. Histologic analysis of mice liver and adipose tissue showed that SCH administration attenuated hepatic steatosis and hypertrophy of adipose tissue. In overall, the results show that SCH can potentially be used to treat metabolic syndrome (MetS) by enhancing glucose metabolism and inhibiting lipogenesis through activating AMP-activated protein kinase (AMPK) and its downstream signaling. Furthermore, it seems to be a feasible drug repurposing strategy for drugs originating from alternative medicine to revise the value for buried indications of some herbal prescription in old traditional Chinese Medicine (TCM) classics.

Significance of Serum Adiponectin and Insulin Resistance Levels in Diagnosis of Egyptian Patients with Chronic Liver Disease and HCC

One possible hypothesis for pathogenesis of hepatocellular carcinoma is deregulated expressed adipokines (adipose tissue cytokines). Chronic inflammation in the cirrhotic liver adipose tissue is associated with a modification in adipokine secretion. Changes in serum levels of adiponectin are known to be associated with the development of insulin resistance. Increased insulin resistance is a pathophysiological feature of nonalcoholic fatty liver disease (NAFLD), one of the most common causes of chronic liver disease. In addition, it was suggested that liver cancer development is probably connected with insulin resistance. The aim of this study is to evaluate the significance of serum Adiponectin level and insulin resistance in patients with chronic liver disease and hepatocellular carcinoma. Patient and Methods: 100 patients were enrolled in this cross sectional study and divided as following: Group I: 52 HCV patients with chronic liver disease (CLD).Group II: 48 patients with hepatocellular carcinoma (HCC). For all subjects, Serum Adiponectin and Insulin Resistance parameters (Fasting serum Insulin, Fasting serum Glucose, HOMA IR) were measured. Results: Serum Adiponectin was significantly lower in patients with hepatocellular carcinoma (p=0.000 ) and it is inversely correlated to tumor size and the number (p= 0.0001).Meanwhile, Insulin Resistance parameters (Fasting s. Insulin, Fasting s. Glucose, HOMA IR) were significantly higher in HCC patients than CLD patients (p= 0.0001). Conclusion: Insulin Resistance is significantly associated with the development of HCC. Serum level of Adiponectin may guard against HCC development among patients with chronic liver disease.

The promising role of probiotic and synbiotic therapy in aminotransferase levels and inflammatory markers in patients with nonalcoholic fatty liver disease - a systematic review and meta-analysis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide. The pathogenesis of NAFLD is complex and multifactorial. There is growing evidence that altered gut microbiota plays a key role in NAFLD progression. Probiotics/synbiotics, by modifying gut microbiota, may be a promising treatment choice for NAFLD management.

AIM

The aim of this study was to study the effect of probiotics/synbiotics on various laboratory and radiographic parameters in NAFLD management.

MATERIALS AND METHODS

A systematic review and meta-analysis were carried out according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. We searched PubMed, Medline, and Google Scholar for randomized-controlled trials that studied the role of probiotics/synbiotics in NAFLD. The primary outcome was change in baseline alanine aminotransferase and aspartate aminotransferase in the treatment arm. We used a random-effects model and inverse variance for the continuous data to estimate the mean difference (MD) and the standard mean difference (SMD) in RevMan Version 5.3.

RESULTS

We included 12 randomized-controlled trials for analysis. The intervention arm, which comprised of the probiotic and/or the synbiotic arm, showed a significant improvement in alanine aminotransferase levels, MD=-13.93, confidence interval (CI)=-20.20 to -7.66, P value of less than 0.0001, I=92% and aspartate aminotransferase levels MD=-11.45, CI=-15.15 to -7.74, P value of less than 0.00001, I=91%. There was a reduction in high-sensitivity C-reactive protein levels in the intervention arm, SMD=-0.68, CI=-1.10 to -0.26, P value of 0.001, I=0%. The liver fibrosis score improved in the intervention arm, MD=-0.71, CI=-0.81 to -0.61, P value less than 0.00001, I=0%.

CONCLUSION

Probiotic/synbiotic use improves aminotransaminase levels and reduces proinflammatory marker high-sensitivity C-reactive protein and liver fibrosis in NAFLD patients.

Non-alcoholic fatty liver disease with obesity as an independent predictor for incident gastric and colorectal cancer: a population-based longitudinal study

Background

Colorectal cancer is known to be an extrahepatic complication of non-alcoholic fatty liver disease (NAFLD). However, the interaction of NAFLD with obesity for incident colorectal cancer has not been clarified yet. Moreover, the effect of NAFLD and obesity for incident gastric cancer has not been clarified yet. Thus, we investigated whether NAFLD with or without obesity would be a risk factor for incident gastric cancer as well as colorectal cancer.

Methods

The study period was set from 2003 to 2016. NAFLD was diagnosed by abdominal ultrasonography using standardised criteria. We applied the Cox proportional hazards model to investigate the effect of NAFLD with or without obesity at baseline on incident gastric cancer as well as colorectal cancer. Age, sex, lifestyle factors including smoking states, alcohol consumption and exercise, and diabetes were used as covariates.

Results

During the study period, 27 944 individuals (16 454 men and 11 490 women) were registered in the NAfld in Gifu Area, Longitudinal Analysis study. During the mean (SD) observational period of 2357 (1458) days, incident gastric cancers were diagnosed in 48 individuals (incident rate 0.48 per 1000 person-years) and incident colorectal cancers were diagnosed in 52 individuals (incident rate 0.51 per 1000 person-years). The adjusted HR of NAFLD with obesity for incident gastric cancer was 3.58 (95% CI 1.73 to 7.38, p=0.001) and that for incident colorectal cancer was 2.96 (95% CI 1.73 to 7.38, p=0.003).

Conclusion

NAFLD with obesity was a risk factor for both incident gastric cancer and colorectal cancer in apparently healthy Japanese individuals.

Clinical outcomes in chronic hepatitis C long-term responders to pre-direct antiviral agents: a single-center retrospective study

BACKGROUND

Obesity, type 2 diabetes (T2D), dyslipidemia, arterial hypertension as well as hepatic steatosis (HS) are common conditions that can affect clinical outcomes of patients with chronic hepatitis C (CHC) who achieved sustained virologic response (SVR). The aim of this study was to assess the impact of metabolic cofactors on the occurrence of clinical events during follow-up (FU) in a group of CHC long-term responders (LTRs) to interferon- (IFN) based therapy.

METHODS

A total of 5172 medical records of CHC patients enrolled from 1990 to 2011 were examined; 1034 of 5172 (20%) patients were treated with IFN-based therapy and 382 of 1034 (37%) of them achieved SVR. A total of 188 (49%) LTRs underwent liver biopsy before antiviral treatment. Data on liver and cardiometabolic events such as cirrhosis and its complications, hepatocellular carcinoma, coronary artery disease, arterial hypertension, impaired fasting glucose (IFG)/type 2 diabetes (T2D) and dyslipidemia, were collected over time.

RESULTS

The mean age of the whole cohort was 46±12 years and 114/188 (61%) patients were males. HS was found in 82 of 188 (43.6%) patients and most of them were infected by HCV genotype 3a. The prevalence of obesity, IFG/T2D, dyslipidemia and arterial hypertension was 4.3%, 6.9%, 37.2%, and 5.9%, and was similarly distributed among patients with and without HS. Cirrhosis was histologically diagnosed in 18 of 188 (9.6%) patients. After a median follow-up of 11 years (range 3-21 years), the cumulative incidence of cardiovascular events, IFG/T2D and dyslipidemia was higher in CHC-LTRs who had HS at baseline compared to those without HS (1.2%, 2.3%, and 3.0% vs. 0.4%, 0.8%, and 2.5%, respectively). At multivariable Cox regression analysis, HS was significantly associated to the development of cardiovascular events and IFG/T2D (HR=5.2, 95% CI: 1.3-20.7, P=0.019, and HR=2.6, 95% CI: 1.1-6.2, P=0.027, respectively).

CONCLUSIONS

In CHC-LTRs, HS at baseline may predispose to the development of cardiovascular events and T2D during follow-up emphasizing the importance of an accurate counseling in order to prevent extra-hepatic complications.

Insulin resistance and plasma glucose tolerance abnormalities in Nigerians with chronic liver disease

AIMS

Glucose tolerance abnormalities are frequently observed in patients with chronic liver disease (CLD). Insulin resistance (IR) has been suggested to be a major factor responsible for these abnormalities in CLD. However studies relating IR with severity of CLD are scarce in Nigeria. This study assessed insulin resistance and glucose tolerance abnormalities in CLD and their relationship with the severity of CLD in a tertiary hospital in South-West, Nigeria.

METHODS

This cross sectional study involved 100 subjects with CLD. Ethical clearance was obtained and informed consent was granted by participants. Participants were interviewed using a structured proforma; physical examination and relevant investigations were performed. Insulin resistance was measured using the homeostasis model assessment (HOMA-IR) Data was analysed using Statistical Package for Social Sciences version 20.0 and p value of <0.05 was considered significant.

RESULTS

Mean age of the study participants was 51.9 ± 11.9 years, and mean duration of CLD was 15.9 ± 5.8 months. Glucose tolerance abnormalities were present in 66 subjects (66%) and increased from 16.1% in Child Pugh's class A to 90.0% in class C. HOMA-IR positively correlated with age, body mass index, serum blood glucose, duration and severity of CLD. Increasing age, presence of hepatocellular carcinoma, Child Pugh's class B and class C were associated with glucose tolerance abnormalities.

CONCLUSION

Glucose tolerance abnormalities and insulin resistance were highly prevalent among chronic liver disease subjects studied and seemed to parallel the severity of CLD, determined by the Child Pugh's score.

Transcriptional Regulation of Early Growth Response Gene-1 (EGR1) is Associated with Progression of Nonalcoholic Fatty Liver Disease (NAFLD) in Patients with Insulin Resistance

BACKGROUND The occurrence of nonalcoholic fatty liver disease (NAFLD) is closely related to type 2 diabetes, especially in patients with insulin resistance. The purpose of this research was to elucidate the major genes and transcriptional regulation of insulin resistance in the progression of NAFLD. MATERIAL AND METHODS We downloaded the gene expression matrix of GSE89632 from Gene Expression Omnibus. Then the principal component analysis was used to identify whether the samples were clustered. Differentially expressed genes were identified by limma R package. Enrichment analysis and protein‑protein interaction network was used to find potential function and screening hub genes. We further used ChIP-seq data from ENCODE to predict the transcriptional regulation of hub genes. Finally, we verified the functions of hub genes with clinical information. RESULTS These hub genes were significantly enriched in "response to insulin", "response to glucose", and "fat cell differentiation". ChIP-seq data showed that EGR1 (early growth response gene-1) may play an important role in the transcriptional regulation of SOCS1 (suppressor of cytokine signaling 1), SOCS3 (suppressor of cytokine signaling 3), and Fos gene family in the liver, as the low expression of EGR1 in patients with insulin resistance may promote the occurrence and development of NAFLD. Similarly, correlation analysis showed that EGR1 was positively correlated with the expression of SOCS1, SOCS3, and the genes of Fos gene family, and EGR1 was negatively correlated with the degree of steatosis. CONCLUSIONS Newly identified hub genes and their transcriptional regulation may promote understanding of the molecular mechanisms underlying insulin resistance related to the progression of NAFLD and provide a new therapy target and biomarkers.

Oxidative Stress and Non-Alcoholic Fatty Liver Disease: Effects of Omega-3 Fatty Acid Supplementation

Aging is a complex phenomenon characterized by the progressive loss of tissue and organ function. The oxidative-stress theory of aging postulates that age-associated functional losses are due to the accumulation of ROS-induced damage. Liver function impairment and non-alcoholic fatty liver disease (NAFLD) are common among the elderly. NAFLD can progress to non-alcoholic steatohepatitis (NASH) and evolve to hepatic cirrhosis or hepatic carcinoma. Oxidative stress, lipotoxicity, and inflammation play a key role in the progression of NAFLD. A growing body of evidence supports the therapeutic potential of omega-3 polyunsaturated fatty acids (n-3 PUFA), mainly docosahaexenoic (DHA) and eicosapentaenoic acid (EPA), on metabolic diseases based on their antioxidant and anti-inflammatory properties. Here, we performed a systematic review of clinical trials analyzing the efficacy of n-3 PUFA on both systemic oxidative stress and on NAFLD/NASH features in adults. As a matter of fact, it remains controversial whether n-3 PUFA are effective to counteract oxidative stress. On the other hand, data suggest that n-3 PUFA supplementation may be effective in the early stages of NAFLD, but not in patients with more severe NAFLD or NASH. Future perspectives and relevant aspects that should be considered when planning new randomized controlled trials are also discussed.

Advances in the role of HCV nonstructural protein 5a (NS5A) of 3a genotype in inducing insulin resistance by possible phosphorylation of AKT/PKB

HCV genes interfere with host cellular genes and play crucial role in pathogenesis. The mechanism under which HCV genes induce insulin resistance is not much clear. This study is aimed to examine the role of HCV NS5A in inducing insulin resistance by examining its affect in the phosphorylation level of AKT/PKB. In the present study, HepG2 cells were transfected with HCV NS5A and after 24 hours of transfection, protein was extracted from cells that were pre induced with insulin at three different time intervals i.e. 1hour, 2 hours and 3hours. Dot Blot analysis was performed to study the phosphorylation level of AKT. Results showed that there is clear upregulation of serine 473 phosphorylation level of AKT in NS5A transfected cells as compared with control (without NS5A). In conclusion, upregulation of serine 473 phosphorylation by NS5A of HCV genotype 3a suggests that this gene impairs the normal insulin AKT/PKB signaling pathway that leads towards insulin resistance and Type 2 diabetes mellitus. Therefore, HCV non-structural protein NS5A should be considered as promising candidate to be studied in detail for HCV induced insulin resistance and should be regarded as a therapeutically important target for the prevention of chronic liver diseases.

MiR-15b can target insulin receptor to regulate hepatic insulin signaling in mice

Now diabetes is growing to be a health problems globally. However, its specific pathogenesis still needs further exploration. Here we showed that miR-15b was upregulated in the palmitate-induced HepG2 cells and livers of hyperglycemic mice. At the same time, we confirmed that the insulin receptor was a direct target of miR-15b. Then we found that the manipulation of miR-15b expression level could affect the insulin signaling pathway of HepG2 cells and the inhibition of miR-15b in liver of ob/ob mice can improve insulin sensitivity of mice. Furthermore, our study demonstrated that palmitate could upregulate the expression of miR-15b by activating PPARα. Our findings established PPARα-responsive miR-15b as a critical regulator of hepatic insulin signaling, thus serving as a new potential therapeutic target for diabetes.

The Liver Fat Fraction and Abdominal Subcutaneous and Visceral Fat Volume Distribution in Normal-Weight, Overweight, and Obese Children Using a New Magnetic Resonance Imaging Technique

OBJECTIVES

The purpose of this study was to evaluate liver fat fraction and subcutaneous and visceral fat volumes using new magnetic resonance imaging in normal-weight, overweight, and obese children.

METHODS

Patients at below the 85th percentile of body mass index (BMI) z score (5/25 patients) were assigned to the normal-weight group; patients between 85th and 95th percentile of BMI z score (9/25 patients) were assigned to the overweight group, and patients above the 95th percentile of BMI z score (11/25 patients) were assigned to the obese group. Liver fat fraction and subcutaneous and visceral fat volumes were measured on 3-dimensional volume measurement workstation.

RESULTS

Liver fat fraction and subcutaneous fat volume had weak correlation (r = 0.18, P = 0.411). Liver fat fraction and visceral fat volume revealed weak correlation (r = 0.25, P = 0.672); visceral and subcutaneous fat volume demonstrated strong correlation (r = 0.67, P = 0.047).

CONCLUSIONS

There is strong correlation between subcutaneous fat volume and visceral fat volume in overweight and obese children.

Dyslipidaemia is common among patients with type 2 diabetes: a cross-sectional study at Tema Port Clinic

OBJECTIVE

This study aimed to evaluate dyslipidemia in Ghanaian subjects with type 2 diabetes.

RESULTS

Hundred individuals with type 2 diabetes and 61 apparently healthy controls participated. The prevalence of hypercholesterolemia among persons with type 2 diabetes was 53%. Blood pressure, fasting blood glucose (FBG), triglyceride (TG), low-density lipoproteins (LDL) and alanine transaminase (ALT) levels were higher in persons with type 2 diabetes compared with the control group (p < 0.01). Positive correlations were found within persons with type 2 diabetes for triglyceride vs FBG; ALT vs age and aspartate transaminase (AST) vs TG (p < 0.05 respectively). This study demonstrated hyperlipidemia and poor liver health in persons with type 2 diabetes.

Non-Alcoholic Fatty Liver Disease and Risk of Incident Type 2 Diabetes: Role of Circulating Branched-Chain Amino Acids

Non-alcoholic fatty liver disease (NAFLD) is likely to be associated with elevated plasma branched-chain amino acids (BCAAs) and may precede the development of type 2 diabetes (T2D). We hypothesized that BCAAs may be involved in the pathogenesis of T2D attributable to NAFLD and determined the extent to which plasma BCAAs influence T2D development in NAFLD. We evaluated cross-sectional associations of NAFLD with fasting plasma BCAAs (nuclear magnetic resonance spectroscopy), and prospectively determined the extent to which the influence of NAFLD on incident T2D is attributable to BCAA elevations. In the current study, 5791 Prevention of REnal and Vascular ENd-stage Disease (PREVEND) cohort participants without T2D at baseline were included. Elevated fatty liver index (FLI) ≥60, an algorithm based on triglycerides, gamma-glutamyltransferase, body mass index (BMI) and waist circumference, was used as proxy of NAFLD. Elevated FLI ≥ 60 was present in 1671 (28.9%) participants. Cross-sectionally, BCAAs were positively associated with FLI ≥ 60 (β = 0.208, p < 0.001). During a median follow-up of 7.3 years, 276 participants developed T2D, of which 194 (70.2%) had an FLI ≥ 60 (log-rank test, p < 0.001). Cox regression analyses revealed that both FLI ≥60 (hazard ratio (HR) 3.46, 95% CI 2.45⁻4.87, p < 0.001) and higher BCAA levels (HR 1.19, 95% CI 1.03⁻1.37, p = 0.01) were positively associated with incident T2D. Mediation analysis showed that the association of FLI with incident T2D was in part attributable to elevated BCAAs (proportion mediated 19.6%). In conclusion, both elevated FLI and elevated plasma BCAA levels are associated with risk of incident T2D. The association of NAFLD with T2D development seems partly mediated by elevated BCAAs.

Hepatic miR‑215 target Rictor and modulation of hepatic insulin signalling in rats

Increasing evidence has suggested that hepatic lipid accumulation is associated with hepatic insulin resistance; however, the underlying mechanism is yet to be determined. It was demonstrated that the levels of microRNA-215 (miR-215) expression in the liver of rats fed a high-fat diet were significantly increased compared with rats on a control diet. Additionally, it was revealed via luciferase assays and western blotting that miR-215 targets rapamycin-insensitive companion of mammalian target of rapamycin (Rictor), an important protein in the hepatic insulin signalling pathway. Following overexpression of miR-215 in the H4IIE rat hepatocarcinoma cell line, it was reported that the intracellular insulin signalling pathway was inhibited; conversely, inhibition of miR-215 expression induced this pathway. Furthermore, it was demonstrated via reverse transcription-quantitative polymerase chain reaction analysis that free fatty acids promoted the expression of miR-215. The present study provided a novel mechanistic insight into the association between nonalcoholic fatty liver and hepatic insulin resistance.

Hepatoprotective Potential of Sargassum muticum against STZ-Induced Diabetic Liver Damage in Wistar Rats by Inhibiting Cytokines and the Apoptosis Pathway

Liver inflammation and necrosis are the foremost problems interlinked with diabetes mellitus (DM). The methanolic extract of Sargassum muticum (MESM) plays a hepatoprotective role in streptozotocin- (STZ-) induced hepatic injury. In this study, STZ exposure induced diabetes that augmented hepatic damage, which was reflected in serum enzyme markers, the cytokine network, and caspase-3 and caspase-9 levels in Group 2. Exposure to the MESM tremendously modulated the levels of hepatic enzyme markers ALP, ACP, ALT, and AST in Groups 3 and 4. The cytokine network was well regulated by suppressing the release of cytokines, and the levels of caspase-3 and caspase-9 were also reduced in Groups 3 and 4. The present study suggests that MESM treatment at 200 and 500 mg protected the liver and also minimizes the glucose level. Thus, the MESM plays a key role in rejuvenating the liver and can modulate diabetes's pathogenic effect by reducing the glucose level.

Interesterified Fats Induce Deleterious Effects on Adipose Tissue and Liver in LDLr-KO Mice

Interesterified fats are being widely used by the food industry in an attempt to replace trans fatty acids. The effect of interesterified fats containing palmitic or stearic acids on lipid metabolism and inflammatory signaling pathways in adipose and hepatic tissues was evaluated. Male LDLr-KO mice were fed a high-fat diet containing polyunsaturated (PUFA), palmitic (PALM), palmitic interesterified (PALM INTER), stearic (STEAR), or stearic interesterified (STEAR INTER) fats for 16 weeks. The expression of genes and protein levels involved in lipid metabolism and inflammatory processes in liver and white adipose tissue was determined by quantitative RT-PCR and by Western blot, respectively. The infiltration of inflammatory cells in hepatic and adipose tissues was determined by eosin and hematoxylin, while liver collagen content was determined by Sirius Red staining. Both interesterified fats increased liver collagen content and JNK phosphorylation. Additionally, the STEAR INTER group developed nonalcoholic steatohepatitis (NASH) associated with higher neutrophil infiltration. PALM INTER induced adipose tissue expansion and enlargement of adipocytes. Furthermore, PALM INTER triggered increased IKK phosphorylation and TNFα protein content, conditions associated with the upstream activation of the NFkB signaling pathway. STEAR INTER induced NASH, while PALM INTER triggered hepatic fibrosis and adipocyte hypertrophy with inflammatory response in LDLr-KO mice.

Sarcopenia in patients with non-alcoholic fatty liver disease: is it a clinically significant entity?

Sarcopenia, described as the loss of muscle mass and/or strength, is gaining importance as it can be increasingly related to many chronic diseases. It is also associated with chronic liver disease, and recently it has been more frequently linked to non-alcoholic fatty liver disease (NAFLD) in particular. Both sarcopenia and NAFLD are subject to complex and intermingled pathophysiological processes, of which some are in common. Furthermore, it is presently unclear if sarcopenia directly contributes to NAFLD or vice versa. The mechanisms that are involved may include obesity, insulin resistance, vitamin D deficiency, aging, physical inactivity and certain cytokines. Current clinical evidence is subject to an important heterogeneity in methods and definitions, with additionally also a relative overrepresentation of evidence in Asian ethnicities. Nonetheless, all studies so far point towards the same association between sarcopenia and NAFLD, including an association with NAFLD-severity and NAFLD-related fibrosis. Since the field is in its infancy, clear definitions and further research are needed to aid to improve understanding of the association between NAFLD and sarcopenia. This can eventually lead to additional potential therapeutic interventions. This review attempts to give an overview of the current published literature that links sarcopenia to NAFLD, followed by a discussion of the presumably involved pathophysiological factors, and ends by discussing current unmet needs.

Serum paraoxonase 1 activity is paradoxically maintained in nonalcoholic fatty liver disease despite low HDL cholesterol

Nonalcoholic fatty liver disease (NAFLD) is characterized by low HDL cholesterol, but the activity of the HDL-associated antioxidative enzyme paraoxonase-1 (PON-1) remains unclear. To determine the association of PON-1 with suspected NAFLD, we measured serum enzyme activity in 7,622 participants of the Prevention of Renal and Vascular End-Stage Disease cohort. A fatty liver index (FLI) ≥60, a proxy of NAFLD, was present in 2,083 participants (27.3%) and coincided with increased prevalence of T2D, metabolic syndrome (MetS), (central) obesity, elevated triglycerides, and low HDL cholesterol (all P < 0.001). In men and women combined, serum PON-1 activity did not vary according to elevated FLI (P = 0.98), whereas in men with elevated FLI PON-1 activity was increased (P = 0.016). In multivariable linear regression analyses (adjusted for age, sex, T2D, MetS, alcohol use, and smoking), PON-1 activity was unexpectedly associated with elevated FLI (β = 0.083; P < 0.001). In a sensitivity analysis (n = 5,126) that excluded subjects with positive cardiovascular history, impaired estimated glomerular filtration rate, elevated urinary albumin excretion, and drug use, PON-1 activity was also independently associated with elevated FLI (β = 0.045; P = 0.017). These results indicate that PON-1 is paradoxically maintained and may even be increased in NAFLD despite inverse associations with metabolic disorders and low HDL cholesterol.

SCCA-IgM as a Potential Biomarker of Non-Alcoholic Fatty Liver Disease in Patients with Obesity, Prediabetes and Diabetes Undergoing Sleeve Gastrectomy

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has a high prevalence in obesity and its presence should be screened. Laparoscopic sleeve gastrectomy (LSG) is an effective treatment for obesity, but its effects on NAFLD are still to be firmly established. The diagnosis of non-alcoholic steatohepatitis (NASH) is currently performed by liver biopsy, a costly and invasive procedure. Squamous cell carcinoma antigen-IgM (SCCA-IgM) is a biomarker of viral hepatitis to hepatocellular carcinoma development and its role in NAFLD to NASH progression has not yet been investigated.

OBJECTIVE

The aim of this study was to evaluate SCCA-IgM as a non-invasive biomarker of NAFLD/NASH in patients with different degrees of metabolic-complicated obesity before and after LSG.

METHOD

Fifty-six patients with obesity were studied before and 12 months after LSG; anthropometric, biochemical, clinical, and imaging data were collected.

RESULTS

At baseline steatosis was strongly associated with the glycaemic profile (p = 0.016) and was already present in prediabetic patients with obesity (82%). Only 3 patients had an SCCA-IgM level above the normal cut-off. SCCA-IgM titre did not change according to glycaemic profile or steatosis. Metabolic and inflammatory factors and transaminases significantly reduced after LSG-induced weight loss, except for SCCA-IgM. The ALT/AST ratio decreased post-LSG correlated with BMI (r = 0.297, p = 0.031), insulin (r = 0.354, p = 0.014), and triglycerides (r = 0.355, p = 0.009) reduction.

CONCLUSIONS

Our results confirm the tight link between NAFLD and metabolic complications, suggesting prediabetes as a new risk factor of steatosis. SCCA-IgM does not seem to have a role in the identification and prognosis of NAFLD.

Sodium tanshinone IIA sulfonate ameliorates hepatic steatosis by inhibiting lipogenesis and inflammation

Non-alcoholic fatty liver disease (NAFLD) is becoming an epidemic disease in adults and children worldwide. Importantly, there are currently no approved treatments available for NAFLD. This study aims to investigate the potential applications of sodium tanshinone IIA sulfonate (STS) on improving the NAFLD condition using both in vitro and in vivo approaches. The results showed that STS markedly inhibited lipid accumulation in oleic acid (OA) and palmitic acid (PA) treated HepG2 and primary immortalized human hepatic (PIH) cells. STS suppressed lipogenesis by inhibiting expression of sterol regulatory element binding transcription factor 1 (SREBF1), fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD). In addition, STS reduced inflammation in cells treated with OA-PA, shown by decreased transcriptional levels of tumor necrosis factor (TNF), transforming growth factor beta 1 (TGFB1) and interleukin 1 beta (IL1B). Consistently, protective effects on hepatic steatosis in db/db mice were observed after STS administration, demonstrated by decreased lipid accumulation in mouse hepatocytes. This protective effect might be associated with STS induced activation of sirtuin 1 (SIRT1)/protein kinase AMP-activated catalytic subunit alpha 1 (PRKAA1) pathways. Our findings suggest a potential therapeutic role for STS in the treatment of NAFLD.

Resveratrol: from enhanced biosynthesis and bioavailability to multitargeting chronic diseases

Resveratrol, a phytoalexin with a wide range of pharmacological properties is synthesised by plants in response to stress, injury, infection or UV radiations. As it is a secondary metabolite with many health promoting properties, various methods employing microorganisms and genetic manipulation of different synthetic enzymes, have been comprehensively studied to increase its production. Its rapid metabolism and low bioavailability have been addressed by the use of bio enhancers and nano-formulations. This flavonoid is extensively researched due to its pharmacological properties such as anti-oxidative, anti-inflammatory and immuno-modulating effects. Knowledge of these properties of resveratrol has led to elaborate studies on its effect on diabetes, neurodegenerative diseases, cancer, ageing, obesity and cardiovascular diseases. At molecular level it targets sirtuin, adenosine monophosphate kinase, nuclear Factor-κB, inflammatory cytokines, anti-oxidant enzymes along with cellular processes such as angiogenesis, apoptosis, mitochondrial biogenesis, gluconeogenesis and lipid metabolism. This review discusses the properties of resveratrol and the different approaches of addressing the unfavourable synthesis and pharmacokinetics of this stilbene. Pre-clinical evaluations of resveratrol on diabetes mellitus, cardiovascular and neurological diseases are elaborately discussed and the underlying pathways involved in its therapeutic activity have been given paramount importance. Following the pre-clinical studies, clinical trials on the same reveal the efficacy of resveratrol in the effective management of these diseases. This review provides an intricate insight on resveratrol's significance from a dietary component to a therapeutic agent.

Ultrasound Entropy Imaging of Nonalcoholic Fatty Liver Disease: Association with Metabolic Syndrome

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of advanced liver diseases. Fat accumulation in the liver changes the hepatic microstructure and the corresponding statistics of ultrasound backscattered signals. Acoustic structure quantification (ASQ) is a typical model-based method for analyzing backscattered statistics. Shannon entropy, initially proposed in information theory, has been demonstrated as a more flexible solution for imaging and describing backscattered statistics without considering data distribution. NAFLD is a hepatic manifestation of metabolic syndrome (MetS). Therefore, we investigated the association between ultrasound entropy imaging of NAFLD and MetS for comparison with that obtained from ASQ. A total of 394 participants were recruited to undergo physical examinations and blood tests to diagnose MetS. Then, abdominal ultrasound screening of the liver was performed to calculate the ultrasonographic fatty liver indicator (US-FLI) as a measure of NAFLD severity. The ASQ analysis and ultrasound entropy parametric imaging were further constructed using the raw image data to calculate the focal disturbance (FD) ratio and entropy value, respectively. Tertiles were used to split the data of the FD ratio and entropy into three groups for statistical analysis. The correlation coefficient r, probability value p, and odds ratio (OR) were calculated. With an increase in the US-FLI, the entropy value increased (r = 0.713; p < 0.0001) and the FD ratio decreased (r = –0.630; p < 0.0001). In addition, the entropy value and FD ratio correlated with metabolic indices (p < 0.0001). After adjustment for confounding factors, entropy imaging (OR = 7.91, 95% confidence interval (CI): 0.96–65.18 for the second tertile; OR = 20.47, 95% CI: 2.48–168.67 for the third tertile; p = 0.0021) still provided a more significant link to the risk of MetS than did the FD ratio obtained from ASQ (OR = 0.55, 95% CI: 0.27–1.14 for the second tertile; OR = 0.42, 95% CI: 0.15–1.17 for the third tertile; p = 0.13). Thus, ultrasound entropy imaging can provide information on hepatic steatosis. In particular, ultrasound entropy imaging can describe the risk of MetS for individuals with NAFLD and is superior to the conventional ASQ technique.

Long-term effects of increased protein intake after weight loss on intrahepatic lipid content and implications for insulin sensitivity: a PREVIEW study

The aim of this study was to assess the effects of a weight maintenance period comprising two diets differing in protein intake, after weight loss, on intrahepatic lipid content and implications for insulin sensitivity. A total of 25 participants [body mass index (BMI): 31.1 (3.5 kg/m²; intrahepatic lipid (IHL): 8.7 (8.3%; fasting glucose: 6.4 (0.6 mmol/l; homeostatic model assessment for insulin resistance (HOMA-IR): 3.7 (1.6; Matsuda index: 3.4 (2.9] started an 8-wk low-energy diet followed by a 2-yr weight maintenance period with either high protein or medium protein dietary guidelines. At baseline, after 6 mo, and after 2 yr, IHL, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were determined by magnetic resonance spectroscopy/imaging. Glucose and insulin concentrations, determined during an oral glucose challenge, were used to assess the HOMA-IR and Matsuda insulin sensitivity index (ISI). Protein intake was measured with 24-h urinary nitrogen excretion. Protein intake, BMI, IHL, VAT, SAT, HOMA-IR, and ISI did not change differently between the groups during the intervention. In the whole group, BMI, IHL, VAT, SAT, HOMA-IR, and ISI were favorably changed at 6 mo and 2 yr compared with baseline ( P < 0.05). Mixed-model analysis showed that independent of BMI, protein intake (g/d) at 6 mo was inversely related to IHL (coefficient: -0.04; P < 0.05) and VAT (coefficient: -0.01; P < 0.05). Overall, IHL was positively related to HOMA-IR (coefficient: 0.10; P < 0.01) and inversely related to ISI (coefficient: -0.17; P < 0.01), independent of BMI. A 2-yr medium- to high-protein energy-restricted diet reduced IHL and VAT. Independently of changes in BMI, IHL was inversely related to insulin sensitivity.

Clinical relevance of reporting fatty liver on ultrasound in asymptomatic patients during routine health checkups

OBJECTIVE

Ultrasonography is an efficient technique for detecting fatty liver. Its sensitivity and specificity in detecting moderate to severe fatty liver are comparable to those of histology. Fatty liver is associated with abnormal lipid and lipoprotein metabolism and insulin resistance, metabolic syndrome, cardiovascular/renal disease, type 2 diabetes, and other conditions. This study was performed to compare the serum lipid profiles and serum glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), and glycosylated hemoglobin (HbA1c) levels in patients diagnosed with fatty liver on ultrasonography versus controls without fatty liver and evaluate the clinical relevance of an ultrasound diagnosis of fatty liver in routine health checkups.

METHODS

This hospital-based cross-sectional study included 390 patients who underwent health checkups; 226 were diagnosed with fatty liver (cases) and 164 were not (controls). The lipid profile, serum GOT and GPT levels, and HbA1c level were compared between the cases and controls.

RESULTS

The cases had considerably higher levels of lipids, liver enzymes (serum GOT and GPT), and HbA1c than controls.

CONCLUSION

Ultrasonography is a noninvasive simple tool for early detection of fatty liver in asymptomatic patients and can help clinicians achieve early detection of metabolic syndrome.

Plasma lecithin:cholesterol acyltransferase and phospholipid transfer protein activity independently associate with nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent condition which contributes to atherogenic apolipoprotein B dyslipoproteinemias. Lecithin:cholesterol acyltransferase (LCAT) and phospholipid transfer protein (PLTP) are both synthesized by the liver and are important in lipid metabolism. Here, we interrogated the impact of NAFLD on plasma LCAT and PLTP activities.

METHODS

Plasma LCAT activity (exogenous substrate assay) and PLTP activity (phospholipid vesicles-HDL assay) were determined in 348 subjects (279 men; 81 subjects with type 2 diabetes (T2DM); 123 with metabolic syndrome (MetS)). A Fatty Liver Index (FLI) ≥60 was used as a proxy of NAFLD. Insulin resistance was determined by homoeostasis model assessment (HOMA-IR).

RESULTS

A total of 147 participants had an FLI ≥60 coinciding with T2DM and MetS (P < 0.001 for each). Plasma LCAT activity and PLTP activity were on average 12% and 5% higher, respectively, in subjects with an FLI ≥ 60 (P < 0.001 for each). In age- and sex-adjusted partial linear regression analysis, LCAT activity and PLTP activity were positively related to various obesity measures and HOMA-IR (P < 0.001 for each). In multivariable linear regression analyses adjusted for age and sex, LCAT activity was associated with an FLI ≥ 60 independent of T2DM and MetS, the waist/hip ratio, or HOMA-IR (β = 0.307 to 0.366, P < 0001 for all models). PLTP activity was also associated with an FLI ≥ 60 independent of these variables (β = 0.151 to 0223, P = 0.013 to 0.001).

CONCLUSION

NAFLD, as inferred from an FLI≥60, confers higher plasma LCAT and to a lesser extent PLTP activity, even when taking account of T2DM, MetS, central obesity and insulin resistance.

GLP-2 Dysregulates Hepatic Lipoprotein Metabolism, Inducing Fatty Liver and VLDL Overproduction in Male Hamsters and Mice

Fundamental complications of insulin resistance and type 2 diabetes include the development of nonalcoholic fatty liver disease and an atherogenic fasting dyslipidemic profile, primarily due to increases in hepatic very-low-density lipoprotein (VLDL) production. Recently, central glucagon-like peptide-2 receptor (GLP2R) signaling has been implicated in regulating hepatic insulin sensitivity; however, its role in hepatic lipid and lipoprotein metabolism is unknown. We investigated the role of glucagon-like peptide-2 (GLP-2) in regulating hepatic lipid and lipoprotein metabolism in Syrian golden hamsters, C57BL/6J mice, and Glp2r-/- mice consuming either a normal chow or high-fat diet (HFD). In the chow-fed hamsters, IP GLP-2 administration significantly increased fasting dyslipidemia, hepatic VLDL production, and the expression of key genes involved in hepatic de novo lipogenesis. In HFD-fed hamsters and chow-fed mice, GLP-2 administration exacerbated or induced hepatic lipid accumulation. HFD-fed Glp2r-/- mice displayed reduced glucose tolerance, VLDL secretion, and microsomal transfer protein lipid transfer activity, as well as exacerbated fatty liver. Thus, we conclude that GLP-2 plays a lipogenic role in the liver by increasing lipogenic gene expression and inducing hepatic steatosis, fasting dyslipidemia, and VLDL overproduction. In contrast, the lack of Glp2r appears to interfere with VLDL secretion, resulting in enhanced hepatic lipid accumulation. These studies have uncovered a role for GLP-2 in maintaining hepatic lipid and lipoprotein homeostasis.

miR‑338‑3p mediates gluconeogenesis via targeting of PP4R1 in hepatocytes

Hyperglycaemia is a characteristic of type 2 diabetes. In hepatocytes, impaired insulin sensitivity leads to increased gluconeogenesis and decreased glycogenesis. MicroRNA (miR)‑338‑3p is associated with tumour necrosis factor (TNF)‑α‑induced suppression of hepatic glycogenesis via regulation of protein phosphatase 4 regulatory subunit 1 (PP4R1). However, the effect of miR‑338‑3p on gluconeogenesis in hepatocytes remains unknown. In a previous study, it was demonstrated that miR‑338‑3p is downregulated in the livers of mice and in mouse HEPA1‑6 hepatocytes following treatment with TNF‑α. In the present study, the effect of miR‑338‑3p on TNF‑α‑induced gluconeogenesis in hepatocytes was investigated. The levels of phosphorylated‑FOXO1/FOXO1, phosphoenolpyruvate carboxykinase (PEPCK), peroxisome proliferator‑activated receptor γ coactivator (PGC‑1α) and glucose‑6‑phosphatase (G6Pase) were measured by western blotting. The mRNA levels of PEPCK, PGC‑1α and G6Pase were determined by quantitative polymerase chain reaction. Pyruvate tolerance testing was used to determine the gluconeogenesis of mouse livers. The results demonstrated that treatment with TNF‑α resulted in increased levels of gluconeogenesis in the livers of mice and decreased miR‑338‑3p expression levels in HEPA1‑6 cells. Overexpression of miR‑338‑3p reversed TNF‑α‑induced glucose production via enhancement of phosphorylated forkhead box O1 levels and downregulation of the expression levels of genes associated with gluconeogenesis, including peroxisome proliferator‑activated receptor γ coactivator‑1α, phosphoenolpyruvate carboxykinase and glucose‑6‑phosphatase. However, inhibition of miR‑338‑3p expression was revealed to enhance gluconeogenesis in the livers of mice and in HEPA1‑6 cells. Furthermore, downregulation of PP4R1 was revealed to attenuate the effect on glucose production following treatment with miR‑338‑3p inhibitors. In conclusion, the results of the present study revealed that miR‑338‑3p may be involved in TNF‑α‑mediated gluconeogenesis via targeting of PP4R1 in hepatocytes.

Catalase and nonalcoholic fatty liver disease

Obesity and insulin resistance are considered the main causes of nonalcoholic fatty liver disease (NAFLD), and oxidative stress accelerates the progression of NAFLD. Free fatty acids, which are elevated in the liver by obesity or insulin resistance, lead to incomplete oxidation in the mitochondria, peroxisomes, and microsomes, leading to the production of reactive oxygen species (ROS). Among the ROS generated, H₂O₂ is mainly produced in peroxisomes and decomposed by catalase. However, when the H₂O₂ concentration increases because of decreased expression or activity of catalase, it migrates to cytosol and other organelles, causing cell injury and participating in the Fenton reaction, resulting in serious oxidative stress. To date, numerous studies have been shown to inhibit the pathogenesis of NAFLD, but treatment for this disease mainly depends on weight loss and exercise. Various molecules such as vitamin E, metformin, liraglutide, and resveratrol have been proposed as therapeutic agents, but further verification of the dose setting, clinical application, and side effects is needed. Reducing oxidative stress may be a fundamental method for improving not only the progression of NAFLD but also obesity and insulin resistance. However, the relationship between NAFLD progression and antioxidants, particularly catalase, which is most commonly expressed in the liver, remains unclear. Therefore, this review summarizes the role of catalase, focusing on its potential therapeutic effects in NAFLD progression.

Time-restricted feeding suppresses excess sucrose-induced plasma and liver lipid accumulation in rats

The etiology of metabolic syndrome involves several complicated factors. One of the main factors contributing to metabolic syndrome has been proposed to be excessive intake of sucrose, which disturbs hepatic lipid metabolism, resulting in fatty liver. However, the mechanism by which sucrose induces fatty liver remains to be elucidated. Considering feeding behavior important for metabolism, we investigated whether time-restricted feeding of high sucrose diet (HSD), only in the active phase (the dark phase of the daily light/dark cycle), would ameliorate adverse effects of sucrose on lipid homeostasis in rats. Male Wistar rats, fed either an ad libitum (ad lib.) or time-restricted control starch diet (CD) or HSD were investigated. Rats fed ad lib. (CD and HSD) completed approximately 20% of food intake in the daytime. Time-restricted feeding did not significantly suppress total food intake of rats. However, time-restricted feeding of HSD significantly suppressed the increased plasma triglyceride levels. Moreover, time-restricted feeding also ameliorated HSD-induced liver lipid accumulation, whereas circadian oscillations of liver clock gene or transcriptional factor gene expression for lipid metabolism were not altered significantly. These results demonstrated that restricting sucrose intake only during the active phase in rats ameliorates the abnormal lipid metabolism caused by excess sucrose intake.

Suppression of NF-κB activation by PDLIM2 restrains hepatic lipogenesis and inflammation in high fat diet induced mice

Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis, insulin resistance, dyslipidemia and a systemic pro-inflammatory response, a leading cause of cirrhosis and hepatocellular carcinoma. Here, we showed that PDZ-LIM domain-containing protein 2 (PDLIM2) was an effective suppressor of steatohepatitis. After 16 weeks on a high fat diet (HFD), obesity, insulin resistance, hepatic dyslipidemia and inflammation were markedly aggravated in PDLIM2-knockout (KO) mice. PDLIM2 deletion resulted in lipid accumulation in liver tissue samples of HFD-induced mice, as evidenced by the significant increase of hepatic TG and TC through reducing the expression of lipogenesis- and transcriptional regulators of lipid metabolism-related genes and enhancing fatty acid oxidation-associated molecules. In addition, PDLIM2-ablation promoted the expression of pro-inflammatory cytokines by activating nuclear factor kappa-B (NF-κB) signaling pathway, as supported by the remarkable increase of phosphorylated IKKβ, IκBα and NF-κB expressions in liver of HFD-fed mice. Of note, the in vitro study demonstrated that PDLIM2 ablation-enhanced inflammatory response and disorder of lipid metabolism were abrogated by suppressing NF-κB activity. Collectively, the findings could lead to the development of potential therapeutic strategy to prevent NAFLD and associated metabolic disorders by targeting PDLIM2.

Chronic liver diseases and the potential use of S-adenosyl-L-methionine as a hepatoprotector

Chronic liver diseases result in overall deterioration of health status and changes in metabolism. The search for strategies to control and combat these hepatic diseases has witnessed a great boom in the last decades. Nutritional therapy for controlling and managing liver diseases may be a positive influence as it improves the function of the liver. In this review, we focus mainly on describing liver conditions such as nonalcoholic fatty liver disease, and intrahepatic cholestasis as well as using S-adenosyl-L-methionine as a dietary supplement and its potential alternative therapeutic effect to correct the hepatic dysfunction associated with these conditions.

Does iris(in) bring bad news or good news?

Irisin, a novel myokine produced in response to physical activity, promotes white-to-brown fat transdifferentiation. The name irisin referred to the ancient Greek goddess Iris, the messenger who delivered (bad) news from the gods. In mice, it has been demonstrated that irisin plays a key role in metabolic regulation, energy expenditure and glucose homeostasis. New findings from various studies carried out in both animals and humans suggest that irisin might also have other favorable effects, such as increasing bone cortical mass, preventing hepatic lipid accumulation, and improving cognitive functions, thus mediating many exercise-induced health benefits. However, data on the role and function of irisin in humans have prompted controversy, due mostly to the only recent confirmation of the presence of irisin in humans. Another strong limitation to the understanding of irisin mechanisms of action is the lack of knowledge about its receptor, which until now remains unidentified in humans and in animals. This review presents an overall analysis of the history of irisin, its expression, and its involvement in health, especially in humans. Level of Evidence Level V, review.

Cholesterol efflux capacity is impaired in subjects with an elevated Fatty Liver Index, a proxy of non-alcoholic fatty liver disease

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) parallels the obesity epidemic and associates with components of the metabolic syndrome (MetS). Cholesterol efflux capacity (CEC) represents a key metric of high density lipoprotein (HDL) function which may predict atherosclerotic cardiovascular disease (CVD). Here we assessed the relationship of CEC with NAFLD.

METHODS

CEC was determined from THP-1 macrophage foam cells towards apolipoprotein B-depleted plasma among 639 subjects (454 men; 36 subjects with type 2 diabetes mellitus (T2D); 226 with MetS), participating in the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study. A Fatty Liver Index (FLI) ≥ 60 was used as a proxy of NAFLD.

RESULTS

372 participants had a FLI ≥60, which coincided with an increased prevalence of T2D and MetS (p = 0.009 and p < 0.001), as well as with central obesity, higher systolic blood pressure, glucose, total cholesterol, triglycerides and high sensitivity C-reactive protein (hsCRP), and decreased HDL cholesterol (p < 0.001 for each). In multivariable linear regression analyses, CEC was inversely associated with an elevated FLI, when taking account of clinical covariates (fully adjusted model: β = -0.091, p = 0.043), and alternatively when taking account of systolic blood pressure, waist/hip ratio, glucose, HDL cholesterol, triglycerides and hsCRP (fully adjusted model: β = -0.103, p = 0.034).

CONCLUSIONS

Impaired CEC is associated with NAFLD, as inferred from a FLI≥60, even when taking account of lower HDL cholesterol and enhanced low-grade chronic inflammation. Reduced CEC could contribute to accelerated CVD in NAFLD patients.

Mechanisms of NAFLD development and therapeutic strategies

There has been a rise in the prevalence of nonalcoholic fatty liver disease (NAFLD), paralleling a worldwide increase in diabetes and metabolic syndrome. NAFLD, a continuum of liver abnormalities from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH), has a variable course but can lead to cirrhosis and liver cancer. Here we review the pathogenic and clinical features of NAFLD, its major comorbidities, clinical progression and risk of complications and in vitro and animal models of NAFLD enabling refinement of therapeutic targets that can accelerate drug development. We also discuss evolving principles of clinical trial design to evaluate drug efficacy and the emerging targets for drug development that involve either single agents or combination therapies intended to arrest or reverse disease progression.

Acetone fraction from Sechium edule (Jacq.) S.w. edible roots exhibits anti-endothelial dysfunction activity

ETHNOPHARMACOLOGICAL RELEVANCE

A recent ethnomedical survey on medicinal plants grown in Mexico revealed that Sechium edule (Jacq.) Sw. (Cucurbitaceae) is one of the most valued plant species to treat cardiovascular diseases, including hypertension. Fruits, young leaves, buds, stems, and tuberous roots of the plant are edible. Considering that endothelial dysfunction induced by Angiotensin II plays an important role in the pathogenesis of hypertension and is accompanied by a prooxidative condition, which in turn induces an inflammatory state, vascular remodeling, and tissue damage, and that S. edule has been reported to possess antioxidant, anti-inflammatory and antihypertensive activity, its capability to control endothelial dysfunction was also assessed.

AIM OF THE STUDY

To assess in vivo the anti-endothelial dysfunction activity of the acetone fraction (rSe-ACE) of the hydroalcoholic extract from S. edule roots.

MATERIALS AND METHODS

Endothelial dysfunction was induced in female C57BL/6 J mice by a daily intraperitoneal injection of angiotensin II for 10 weeks. Either rSe-ACE or losartan (as a control) were co-administered with angiotensin II for the same period. Blood pressure was measured at weeks 0, 5, and 10. Kidney extracts were prepared to determine IL1β, IL4, IL6, IL10, IL17, IFNγ, TNFα, and TGFβ levels by ELISA, along with the prooxidative status as assessed by the activity of antioxidant enzymes. The expression of ICAM-1 was evaluated by immunohistochemistry in kidney histological sections. Kidney and hepatic damage, as well as vascular tissue remodeling, were studied.

RESULTS

The rSe-ACE fraction administered at a dose of 10 mg/kg was able to control hypertension, as well as the prooxidative and proinflammatory status in kidney as efficiently as losartan, returning mice to normotensive levels. Additionally, the fraction was more efficient than losartan to prevent liver and kidney damage. Phytochemical characterization identified cinnamic acid as a major compound, and linoleic, palmitic, and myristic acids as the most abundant non-polar components in the mixture, previously reported to aid in the control of hypertension, inflammation, and oxidative stress, three important components of endothelial dysfunction.

IN CONCLUSION

this study demonstrated that rSe-ACE has anti-endothelial dysfunction activity in an experimental model and highlights the role of cinnamic acid and fatty acids in the observed effects.

Conversion of Sugar to Fat: Is Hepatic de Novo Lipogenesis Leading to Metabolic Syndrome and Associated Chronic Diseases?

Epidemiologic studies suggest a link between excess sugar consumption and obesity, fatty liver disease, metabolic syndrome, and type 2 diabetes mellitus. One important pathway that may link these metabolic diseases to sugar consumption is hepatic conversion of sugar to fat, a process known as de novo lipogenesis (DNL). Mechanistic studies have shown that diets high in simple sugars increase both DNL and liver fat. Importantly, removal of sugar from diets of children with obesity for only 9 days consistently reduced DNL and liver fat and improved glucose and lipid metabolism. Although the sugar and beverage industries continue to question the scientific evidence linking high-sugar diets to metabolic diseases, major health organizations now make evidence-based recommendations to limit consumption of simple sugars to no more than 5% to 10% of daily intake. Clear recommendation about moderating sugar intake to patients may be an important nonpharmacologic tool to include in clinical practice.

Probing insulin sensitivity in diabetic kidney disease: is there a stronger role for functional imaging?

Clinical and experimental evidence support a cause-effect relationship between altered insulin signaling and development of kidney disease of metabolic and non-metabolic origin. However, the current criteria to measure and/or estimate the insulin resistance (IR) are available as research tool but are very difficult to implement in the clinical practice. Therefore, a better understanding of the key players contributing to IR may lead to the development of new non-invasive tools to assess organ-specific insulin sensitivity (IS). We will therefore first introduce the concept that IR and kidney disease may be causally linked as suggested by clinical and experimental studies. We will then, expand on the potential mechanisms leading to altered renal insulin signaling. After reviewing the limitation of currently available strategies to determine IR, this review article will focus on imaging techniques that could be utilized to determine renal IR and that could be tested to predict kidney disease development and progression.

Alpha-Mangostin Improves Insulin Secretion and Protects INS-1 Cells from Streptozotocin-Induced Damage

Alpha (α)-mangostin, a yellow crystalline powder with a xanthone core structure, is isolated from mangosteen (Garcinia mangostana), which is a tropical fruit of great nutritional value. The aim of the present study was to investigate the anti-diabetic effects of α-mangostin and to elucidate the molecular mechanisms underlying its effect on pancreatic beta (β)-cell dysfunction. To assess the effects of α-mangostin on insulin production, rat pancreatic INS-1 cells were treated with non-toxic doses of α-mangostin (1⁻10 μM) and its impact on insulin signaling was examined by Western blotting. In addition, the protective effect of α-mangostin against pancreatic β-cell apoptosis was verified by using the β-cell toxin streptozotocin (STZ). Our results showed that α-mangostin stimulated insulin secretion in INS-1 cells by activating insulin receptor (IR) and pancreatic and duodenal homeobox 1 (Pdx1) followed by phosphorylation of phospho-phosphatidylinositol-3 kinase (PI3K), Akt, and extracellular signal regulated kinase (ERK) signaling cascades, whereas it inhibited the phosphorylation of insulin receptor substrate (IRS-1) (Ser1101). Moreover, α-mangostin was found to restore the STZ-induced decrease in INS-1 cell viability in a dose-dependent manner. In addition, treatment of INS-1 cells with 50 μM STZ resulted in an increase in intracellular reactive oxygen species (ROS) levels, which was represented by the fluorescence intensity of 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). This oxidative stress was decreased by co-treatment with 5 μM α-mangostin. Similarly, marked increases in the phosphorylation of P38, c-Jun N-terminal kinase (JNK), and cleavage of caspase-3 by STZ were decreased significantly by co-treatment with 5 μM α-mangostin. These results suggest that α-mangostin is capable of improving insulin secretion in pancreatic β-cells and protecting cells from apoptotic damage.

Diabetes Mellitus and Liver Surgery: The Effect of Diabetes on Oxidative Stress and Inflammation

Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycaemia and high morbidity worldwide. The detrimental effects of hyperglycaemia include an increase in the oxidative stress (OS) response and an enhanced inflammatory response. DM compromises the ability of the liver to regenerate and is particularly associated with poor prognosis after ischaemia-reperfusion (I/R) injury. Considering the growing need for knowledge of the impact of DM on the liver following a surgical procedure, this review aims to present recent publications addressing the effects of DM (hyperglycaemia) on OS and the inflammatory process, which play an essential role in I/R injury and impaired hepatic regeneration after liver surgery.