Gastrointestinal complications of obesity: non-alcoholic fatty liver disease (NAFLD) and its sequelae

Single nucleus RNA-sequencing integrated into risk variant colocalization discovers 17 cell-type-specific abdominal obesity genes for metabolic dysfunction-associated steatotic liver disease

BACKGROUND

Abdominal obesity increases the risk for non-alcoholic fatty liver disease (NAFLD), now known as metabolic dysfunction-associated steatotic liver disease (MASLD).

METHODS

To elucidate the directional cell-type level biological mechanisms underlying the association between abdominal obesity and MASLD, we integrated adipose and liver single nucleus RNA-sequencing and bulk cis-expression quantitative trait locus (eQTL) data with the UK Biobank genome-wide association study (GWAS) data using colocalization. Then we used colocalized cis-eQTL variants as instrumental variables in Mendelian randomization (MR) analyses, followed by functional validation experiments on the target genes of the cis-eQTL variants.

FINDINGS

We identified 17 colocalized abdominal obesity GWAS variants, regulating 17 adipose cell-type marker genes. Incorporating these 17 variants into MR discovers a putative tissue-of-origin, cell-type-aware causal effect of abdominal obesity on MASLD consistently with multiple MR methods without significant evidence for pleiotropy or heterogeneity. Single cell data confirm the adipocyte-enriched mean expression of the 17 genes. Our cellular experiments across human adipogenesis identify risk variant -specific epigenetic and transcriptional mechanisms. Knocking down two of the 17 genes, PPP2R5A and SH3PXD2B, shows a marked decrease in adipocyte lipidation and significantly alters adipocyte function and adipogenesis regulator genes, including DGAT2, LPL, ADIPOQ, PPARG, and SREBF1. Furthermore, the 17 genes capture a characteristic MASLD expression signature in subcutaneous adipose tissue.

INTERPRETATION

Overall, we discover a significant cell-type level effect of abdominal obesity on MASLD and trace its biological effect to adipogenesis.

FUNDING

NIH grants R01HG010505, R01DK132775, and R01HL170604; the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (Grant No. 802825), Academy of Finland (Grants Nos. 333021), the Finnish Foundation for Cardiovascular Research the Sigrid Jusélius Foundation and the Jane and Aatos Erkko Foundation; American Association for the Study of Liver Diseases (AASLD) Advanced Transplant Hepatology award and NIH/NIDDK (P30DK41301) Pilot and Feasibility award; NIH/NIEHS F32 award (F32ES034668); Finnish Diabetes Research Foundation, Kuopio University Hospital Project grant (EVO/VTR grants 2005-2021), the Academy of Finland grant (Contract no. 138006); Academy of Finland (Grant Nos 335443, 314383, 272376 and 266286), Sigrid Jusélius Foundation, Finnish Medical Foundation, Finnish Diabetes Research Foundation, Novo Nordisk Foundation (#NNF20OC0060547, NNF17OC0027232, NNF10OC1013354) and Government Research Funds to Helsinki University Hospital; Orion Research Foundation, Maud Kuistila Foundation, Finish Medical Foundation, and University of Helsinki.

Effect of Cytokeratin-18, C-peptide, MHR, and MACK-3 Biomarkers in Metabolic Dysfunction-Associated Fatty Liver Disease After Laparoscopic Sleeve Gastrectomy

Background

Laparoscopic sleeve gastrectomy (LSG) has emerged as a valuable treatment for various metabolic disorders, including metabolic dysfunction-associated fatty liver disease (MAFLD) in patients with obesity. Consequently, there is a pressing need to develop noninvasive biomarkers for diagnosing and monitoring disease progression.

Objectives

This study aimed to evaluate specific biomarkers, including Cytokeratin-18 (CK-18), C-peptide, monocyte to HDL cholesterol ratio (MHR), and MACK-3, in patients with obesity with MAFLD undergoing LSG.

Design

A prospective cohort study on patients with obesity before and 6 months after the LSG procedure.

Methods

70 patients with obesity with confirmed MAFLD, determined by Transient Elastography (TE), were pre- and 6 months postoperatively tested. Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), lipid profile, ghrelin, leptin, peptide YY, GLP-1, and liver fibrosis scores, including AST/ALT ratio (AAR), Fibrosis-4 index (FIB-4), and BARD Score were tested.

Results

BMI significantly decreased in all participants, with a % excess weight loss of 62.0% ± 15.4%. TE measurements revealed a significant postoperative reduction from 100% to 87.1% (P = .006). All selected biomarkers showed significant postoperative improvement-a significant association of CK-18 with MAFLD markers, including AAR, FIB-4, and BARD score, were found. MACK-3 had positive associations with FIB-4. C-peptide and MHR showed no association with MAFLD markers. Furthermore, there was a positive correlation between CK-18 and MACK-3 tests and between C-peptide and CK-18 and MACK-3. Additionally, a receiver operating characteristic (ROC) curve was constructed, with CK-18 performing the best, with an estimated area under the curve of 0.863.

Conclusion

Serum CK-18 outperformed other selected biomarkers in predicting and monitoring MAFLD in patients with obesity, suggesting its prospective utility in clinical practice. Further studies are needed to validate the accuracy of the MACK-3 test.

Combinatorial Microgels for 3D ECM Screening and Heterogeneous Microenvironmental Culture of Primary Human Hepatic Stellate Cells

Nonalcoholic fatty liver disease affects 30% of the United States population and its progression can lead to nonalcoholic steatohepatitis (NASH), and increased risks for cirrhosis and hepatocellular carcinoma. NASH is characterized by a highly heterogeneous liver microenvironment created by the fibrotic activity of hepatic stellate cells (HSCs). While HSCs have been widely studied in 2D, further advancements in physiologically relevant 3D culture platforms for the in vitro modeling of these heterogeneous environments are needed. In this study, the use of stiffness-variable, extracellular matrix (ECM) protein-conjugated polyethylene glycol microgels as 3D cell culture scaffolds to modulate HSC activation is demonstrated. These microgels as a high throughput ECM screening system to identify HSC matrix remodeling and metabolic activities in distinct heterogeneous microenvironmental conditions are further employed. The 6 kPa fibronectin microgels are shown to significantly increase HSC matrix remodeling and metabolic activities in single or multiple-component microenvironments. Overall, heterogeneous microenvironments consisting of multiple distinct ECM microgels promoted a decrease in HSC matrix remodeling and metabolic activities compared to homogeneous microenvironments. The study envisions this ECM screening platform being adapted to a broad number of cell types to aid the identification of ECM microenvironments that best recapitulate the desired phenotype, differentiation, or drug efficacy.

Body composition assessment of people with overweight/obesity with a simplified magnetic resonance imaging method

To develop a simplified magnetic resonance imaging method (MRI) to assess total adipose tissue (AT) and adipose tissue free mass (ATFM) from three single MRI slices in people with overweight/obesity in order to implement body composition follow-up in a clinical research setting. Body composition of 310 participants (70 women and 240 men, age: 50.8 ± 10.6 years, BMI: 31.3 ± 5.6 kg.m^-2) was assessed with 3 single slices (T6-T7, L4-L5 and at mid-thigh) MRI. Multiple regression analysis was used to develop equations predicting AT and ATFM from these three single slices. Then we implemented a longitudinal phase consisting in a 2-month exercise training program during which we tested the sensitivity of these equations in a subgroup of participants with overweight/obesity (n = 79) by comparing the exercise-induced variations between predicted and measured AT and ATFM. The following equations: total AT = - 12.74105 + (0.02919 × age) + (4.27634 × sex (M = 0, F = 1)) + (0.22008 × weight) + (26.92234 × AT T6-T7) + (23.70142 × AT L4-L5) + (37.94739 × AT mid-thigh) and total ATFM = - 33.10721 + (- 0.02363 × age) + (- 3.58052 × sex (M = 0, F = 1)) + (30.02252 × height) + (0.08549 × weight) + (11.36859 × ATFM T6-T7) + (27.82244 × ATFM L4-L5) + (58.62648 × ATFM mid-thigh) showed an excellent prediction (adjusted R² = 97.2% and R² = 92.5%; CCC = 0.986 and 0.962, respectively). There was no significant difference between predicted and measured methods regarding the AT variations (- 0.07 ± 2.02 kg, p = 0.70) and the ATFM variations (0.16 ± 2.41 kg, p = 0.49) induced by 2-months of exercise training. This simplified method allows a fully accurate assessment of the body composition of people with obesity in less than 20 min (10 min for images acquisition and analysis, respectively), useful for a follow-up.

Combinatorial Microgels for 3D ECM Screening and Heterogeneous Microenvironmental Culture of Primary Human Hepatic Stellate Cells

Non-alcoholic fatty liver disease affects 30% of the United States population and its progression can lead to non-alcoholic steatohepatitis (NASH), which can result in cirrhosis and hepatocellular carcinoma. NASH is characterized by a highly heterogeneous liver microenvironment created by the fibrotic activity of hepatic stellate cells (HSCs). While HSCs have been widely studied in 2D, further advancements in physiologically-relevant 3D culture platforms for the in vitro modeling of these heterogeneous environments are needed. In this study, we have demonstrated the use of stiffness-variable, ECM protein-conjugated polyethylene glycol microgels as 3D cell culture scaffolds to modulate HSC activation. We further employed these microgels as a high throughput ECM screening system to identify HSC matrix remodeling and metabolic activities in distinct heterogeneous microenvironmental conditions. In particular, 6 kPa fibronectin microgels were shown to significantly increase HSC matrix remodeling and metabolic activities in single or multiple component microenvironments. Overall, heterogeneous microenvironments consisting of multiple distinct ECM microgels promoted a decrease in HSC matrix remodeling and metabolic activities compared to homogeneous microenvironments. We envision this ECM screening platform being adapted to a broad number of cell types to aid the identification of ECM microenvironments that best recapitulate the desired phenotype, differentiation, or drug efficacy.

Asperuloside alleviates lipid accumulation and inflammation in HFD-induced NAFLD via AMPK signaling pathway and NLRP3 inflammasome

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a clinical pathological syndrome of hepatic parenchymal cell steatosis caused by excessive lipid deposition, which is the chronic liver disease with the highest incidence in China. Asperuloside (ASP), a kind of iridoid compound, possesses natural pharmacological effects of anti-tumor, anti-inflammatory, antioxidant and anti-obesity. However, whether ASP can improve NAFLD remains unclear.

PURPOSE

We aimed to investigate the effect of ASP on NAFLD mice induced by high-fat diet (HFD), and explore its mechanism in vivo and in vitro.

METHODS

Pharmacodynamics of ASP was studied by HFD induction in NAFLD mice. HepG2 cells were induced by palmitic acid (PA) as cell model to investigate the effect of ASP on lipid deposition and inflammatory infiltration. Expression of Adenosine monophosphate - activated protein kinase (AMPK) signaling pathway and NOD-like receptor pyrin containing 3 (NLRP3) inflammasome were detected by Western blot and RT-PCR. Cytokines IL-1β and TNF-α were detected by ELISA.

RESULTS

ASP alleviated liver injury and inflammatory damage in mice with NAFLD. In addition, ASP improved lipid deposition as well as inflammatory response in HFD-induced NAFLD mice and PA-stimulated HepG2 cells. ASP ameliorated lipid deposition and inflammatory response by regulating the p-AMPK/SREBP-1c signaling pathway and NLRP3 inflammasome.

CONCLUSION

Our results suggest that ASP improve lipid deposition and inflammatory infiltration in NAFLD mice via regulating the AMPK/SREBP-1c signaling pathway and NLRP3 inflammasome, which may be an effective candidate for the treatment of NAFLD.

Advances in metformin for the treatment of non-alcoholic fatty liver disease in children

INTRODUCTION

The increased economic and social burdens for NAFLD worldwide make treating such a disease a significant public health issue. Metformin, a kind of insulin sensitizer generally used to treat type 2 diabetes, has been recently found to have efficacy on children's NAFLD in various areas such as glucolipid metabolism, intestinal bacterial metabolism, oxidative stress, and anti-inflammatory response. This article aims to provide an overview of the possible mechanisms of NAFLD in children and the potential therapeutic application of metformin.

AREAS COVERED

The Cochrane Library, PubMed, Scopus, and EMBASE database was systematically searched on 12 April 2022, using the keywords metformin; non-alcoholic fatty liver disease; and children to identify similar studies. An additional search for recently published research was performed in June 2020.

EXPERT OPINION

Although metformin has been proved to have an excellent therapeutic effect on children's NAFLD; we can still explore its potential impacts and mechanisms from different angles, such as combined medication. At the same time, we should also pay attention to its side effects.

Salvianolic acid B ameliorates non-alcoholic fatty liver disease by inhibiting hepatic lipid accumulation and NLRP3 inflammasome in ob/ob mice

Non-alcoholic fatty liver disease (NAFLD) has high occurrence in the global world, which poses serious threats to human health. Salvianolic acid B (SalB), an extract of the root of Salvia miltiorrhiza, has the protective effect on metabolic homeostasis. However, the mechanism is still unknown. In this study, we used ob/ob mice, a model of NAFLD, to explore the hepatoprotective effects of SalB. The results showed that SalB significantly reduced the body weights and liver weights, and ameliorated plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), hepatic free fatty acid (FFA), total cholesterol (TC) levels, and hepatic TG and TC levels in ob/ob mice. SalB reduced the number of lipid droplets and inhibited hepatic lipogenesis by regulating peroxisome proliferator-activated receptor gamma (PPARγ), fatty acid synthase (FASN), stearoyl-Co A desaturase 1 (SCD1), and cluster of differentiation 36 (CD36). Compared to ob/ob mice, the lower expressions of the pro-inflammatory cytokines, such as interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and F4/80, were observed after SalB treatment. Importantly, SalB treatment inhibited the activation of NLRP3 inflammasome and reduced the severity of liver inflammation. Our findings suggested that SalB improved NAFLD pathology in ob/ob mice by reducing hepatic lipid accumulation and NLRP3 inflammasome activation, which might be the potential hepatoprotective mechanism of SalB.

Live Combined B. subtilis and E. faecium Alleviate Liver Inflammation, Improve Intestinal Barrier Function, and Modulate Gut Microbiota in Mice with Non-Alcoholic Fatty Liver Disease

Background

Non-alcoholic fatty liver disease (NAFLD) is a chronic, progressive liver disease with an increasing incidence rate. This study investigated the protective effects of live combined Bacillus subtilis and Enterococcus faecium (LCBE) on NAFLD, and its possible mechanisms.

Material/Methods

Five-week-old C57BL/6 mice were randomly divided into 3 groups: chow, HFD, and HFD+LCBE groups. The levels of serum biochemical markers, glucose tolerance, insulin, the inflammatory cytokines IL-1β, IL-6, and TNF-α, LPS, and histological staining were measured using commercial kits. qPCR was used to examine the mRNA expression levels of inflammatory cytokines in the liver. Western blotting was used to determine the protein levels of TLR4, NF-κB p65, PPAR-α, and CPT-1 in the liver, and occludin and Claudin1 in the intestine. The intestinal flora of the mice was analyzed by high-throughput sequencing of the V3–V4 region of 16S rDNA.

Results

LCBE significantly lowered the body weight, liver/body weight ratio, and serum glucose level, and increased the serum insulin level in NAFLD mice. In addition, LCBE treatment improved the liver function and lipid profile, decreased the levels of LPS and inflammatory cytokines, and downregulated the expression of TLR4 and NF-κB p65. Moreover, LCBE enhanced the intestinal barrier function by increasing the expression of occludin and Claudin1. Furthermore, LCBE modulated the composition of the gut microbiota by reducing the Firmicutes to Bacteroidetes ratio, and the proportion of inflammation-related and LPS-producing bacteria, thus re-arranging the structure of the gut microbiota.

Conclusions

LCBE protects against NAFLD by alleviating inflammation, restoring the intestinal barrier, and modulating gut microbiota composition.

Hesperetin ameliorates hepatic oxidative stress and inflammation via the PI3K/AKT-Nrf2-ARE pathway in oleic acid-induced HepG2 cells and a rat model of high-fat diet-induced NAFLD

Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver disease. Dietary supplementation has become a promising strategy for managing NAFLD. Hesperetin, a citrus flavonoid, is mainly found in citrus fruits (oranges, grapefruit, and lemons) and possesses multiple pharmacological properties, including anti-cancer, anti-Alzheimer and anti-diabetic effects. However, the anti-NAFLD effect and mechanisms of hesperetin remain unclear. In this study, we investigated the therapeutic effect of hesperetin against NAFLD and the underlying mechanism in vitro and in vivo. In oleic acid (OA)-induced HepG2 cells, hesperetin upregulated antioxidant levels (SOD/GPx/GR/GCLC/HO-1) by triggering the PI3 K/AKT-Nrf2 pathway, alleviating OA-induced reactive oxygen species (ROS) overproduction and hepatotoxicity. Furthermore, hesperetin suppressed NF-κB activation and reduced inflammatory cytokine secretion (TNF-α and IL-6). More importantly, we revealed that this anti-inflammatory effect is attributed to reduced ROS overproduction by the Nrf2 pathway, as pre-treatment with Nrf2 siRNA or an inhibitor of superoxide dismutase (SOD) or/and glutathione peroxidase (GPx) abolished hesperetin-induced NF-κB inactivation and reductions in inflammatory cytokine secretion. In a rat model of high-fat diet (HFD)-induced NAFLD, we confirmed that hesperetin relieved hepatic steatosis, oxidative stress, inflammatory cell infiltration and fibrosis. Moreover, hesperetin activated the PI3 K/AKT-Nrf2 pathway in the liver, increasing antioxidant expression and inhibiting NF-κB activation and inflammatory cytokine secretion. In summary, our results demonstrate that hesperetin ameliorates hepatic oxidative stress through the PI3 K/AKT-Nrf2 pathway and that this antioxidative effect further suppresses NF-κB-mediated inflammation during NAFLD progression. Thus, our study suggests that hesperetin may be an effective dietary supplement for improving NAFLD by suppressing hepatic oxidative stress and inflammation.

Taxifolin ameliorate high-fat-diet feeding plus acute ethanol binge-induced steatohepatitis through inhibiting inflammatory caspase-1-dependent pyroptosis

Excessive alcohol drinking and a high-fat diet (HFD) promote steatohepatitis in the comorbidity of NAFLD and AFLD. Taxifolin (TAX) is a rich dihydroxyflavone compound found in onions, milk thistle and Douglas fir. We aimed to explore the intervention mechanism of TAX on chronic steatohepatitis induced by HFD feeding plus acute ethanol binge. We established an in vivo model by HFD feeding plus a single dose of ethanol binge, and established an in vitro model by oleic acid or palmitic acid on HepG2 cells to induce lipid accumulation. TAX regulated lipid synthesis by inhibiting the expression of SREBP1 and upregulating the PPARγ level. In addition, TAX inhibited the expression of P2X7R, IL-1β, and caspase-1. Moreover, TAX reduced the expression of caspase-1 activation; thereby inhibiting the recruitment of macrophages and neutrophils. TAX also improved the inflammatory response caused by caspase-1 activation in steatotic hepatocytes. TAX exhibited an inhibitory effect on lipid accumulation and caspase-1-related pyroptosis. Collectively, TAX has therapeutic potential as an intervention of steatohepatitis induced by alcohol combined with HFD and for preventing non-alcoholic fatty liver degeneration targeting caspase-1-dependent pyroptosis.

Current NAFLD guidelines for risk stratification in diabetic patients have poor diagnostic discrimination

Patients with type 2 diabetes (T2D) are at risk for non-alcoholic fatty liver disease (NAFLD) and associated complications. This study evaluated the performance of international (EASL-EASD-EASO) and national (DGVS) guidelines for NAFLD risk stratification. Patients with T2D prospectively underwent ultrasound, liver stiffness measurement (LSM) and serum-based fibrosis markers. Guideline-based risk classification and referral rates for different screening approaches were compared and the diagnostic properties of simplified algorithms, genetic markers and a new NASH surrogate (FAST score) were evaluated. NAFLD risk was present in 184 of 204 screened patients (age 64.2 ± 10.7 years; BMI 32.6 ± 7.6 kg/m2). EASL-EASD-EASO recommended specialist referral for 60-77% depending on the fibrosis score used, only 6% were classified as low risk. The DGVS algorithm required LSM for 76%; 25% were referred for specialised care. The sensitivities of the diagnostic pathways were 47-96%. A simplified referral strategy revealed a sensitivity/specificity of 46/88% for fibrosis risk. Application of the FAST score reduced the referral rate to 35%. This study (a) underlines the high prevalence of fibrosis risk in T2D, (b) demonstrates very high referral rates for in-depth hepatological work-up, and (c) indicates that simpler referral algorithms may produce comparably good results and could facilitate NAFLD screening.

In situ visualization of peroxisomal viscosity in the liver of mice with non-alcoholic fatty liver disease by near-infrared fluorescence and photoacoustic imaging

Non-alcoholic fatty liver disease (NAFLD) can gradually develop into hepatic failure, and early diagnosis is crucial to improve treatment efficiency. The occurrence of NAFLD is closely related to lipid metabolism. Peroxisomes act as the first and main site for lipid metabolism in the hepatocytes, so abnormal lipid metabolism might directly affect peroxisomal viscosity. Herein, we developed a new near-infrared fluorescence (NIRF) and photoacoustic (PA) imaging probe (PV-1) for the real-time visualization of peroxisomal viscosity in vivo. This PV-1 encompasses the malononitrile group as the rotor, which emits strong NIRF (at 705 nm) and PA (at 680 nm) signals when rotation is hindered as viscosity increases. Through dual-mode imaging, we discovered distinctly higher viscosity in the liver of NAFLD mice for the first time. We further found the remarkable amelioration of NAFLD upon treatment with N-acetylcysteine (NAC). Therefore, we anticipate that the PV-1 imaging method is promising for the early diagnosis and prognostic evaluation of NAFLD.

Gut microbiota and human NAFLD: disentangling microbial signatures from metabolic disorders

Gut microbiota dysbiosis has been repeatedly observed in obesity and type 2 diabetes mellitus, two metabolic diseases strongly intertwined with non-alcoholic fatty liver disease (NAFLD). Animal studies have demonstrated a potential causal role of gut microbiota in NAFLD. Human studies have started to describe microbiota alterations in NAFLD and have found a few consistent microbiome signatures discriminating healthy individuals from those with NAFLD, non-alcoholic steatohepatitis or cirrhosis. However, patients with NAFLD often present with obesity and/or insulin resistance and type 2 diabetes mellitus, and these metabolic confounding factors for dysbiosis have not always been considered. Patients with different NAFLD severity stages often present with heterogeneous lesions and variable demographic characteristics (including age, sex and ethnicity), which are known to affect the gut microbiome and have been overlooked in most studies. Finally, multiple gut microbiome sequencing tools and NAFLD diagnostic methods have been used across studies that could account for discrepant microbiome signatures. This Review provides a broad insight into microbiome signatures for human NAFLD and explores issues with disentangling these signatures from underlying metabolic disorders. More advanced metagenomics and multi-omics studies using system biology approaches are needed to improve microbiome biomarkers.

Sodium fluorocitrate having inhibitory effect on fatty acid uptake ameliorates high fat diet-induced non-alcoholic fatty liver disease in C57BL/6J mice

Non-alcoholic fatty liver disease (NAFLD) is excessive fat build-up in the liver without alcohol consumption and includes hepatic inflammation and damage. Excessive influx of fatty acids to liver from circulation is thought to be a pathogenic cause for the development of NAFLD. Thus, inhibition of fatty acid intake into hepatocyte would be a maneuver for protection from high fat diet (HFD)-induced NAFLD. This study was initiated to determine whether sodium fluorocitrate (SFC) as a fatty acid uptake inhibitor could prevent palmitate-induced lipotoxicity in hepatocytes and protect the mice from HFD-induced NAFLD. SFC significantly inhibited the cellular uptake of palmitate in HepG2 hepatocytes, and thus prevented palmitate-induced fat accumulation and death in these cells. Single treatment with SFC reduced fasting-induced hepatic steatosis in C57BL/6J mice. Concurrent treatment with SFC for 15 weeks in HFD-fed C57BL/6J mice prevented HFD-induced fat accumulation and stress/inflammatory signal activation in the liver. SFC restored HFD-induced increased levels of serum alanine aminotransferase and aspartate aminotransferases as hepatic injury markers in these mice. SFC treatment also improved HFD-induced hepatic insulin resistance, and thus ameliorated HFD-induced hyperglycemia. In conclusion, inhibition of fatty acid mobilization into liver through SFC treatment can be a strategy to protect from HFD-induced NAFLD.

Type 2 diabetes mellitus: A risk factor for progression of liver fibrosis in middle-aged patients with non-alcoholic fatty liver disease

BACKGROUND AND AIM

The severity of liver fibrosis is strongly associated with prognosis in patients with non-alcoholic fatty liver disease (NAFLD). We evaluated clinical risk factors for progression of liver fibrosis in patients with NAFLD.

METHODS

This study included 1562 middle-aged (36-64 years) patients with NAFLD and less severe liver fibrosis (fibrosis-4 index < 1.3).

RESULTS

During follow-up, 186 patients progressed to advanced fibrosis (fibrosis-4 index > 2.67). The 3-, 5-, 7-, and 10-year cumulative incidence of progression to advanced fibrosis was 4.4%, 6.7%, 11.0%, and 16.7%, respectively. In the univariate analysis, age, albumin concentration, and type 2 diabetes mellitus (T2DM) were significantly associated with progression to advanced fibrosis. Multivariate analysis with adjustment for age, smoking, body mass index, albumin, estimated glomerular filtration rate, dyslipidemia, T2DM, and steatosis showed that age ≥ 50 years (hazard ratio [HR], 2.121; 95% confidence interval [CI], 1.462-3.076; P < 0.001), albumin concentration < 4.2 g/dL (HR, 1.802; 95% CI, 1.285-2.528; P < 0.001), and the presence of T2DM (HR, 1.879; 95% CI, 1.401-2.520; P < 0.001) were independently associated with progression to advanced fibrosis. Conversely, degree of steatosis was not associated with progression to advanced fibrosis. The respective 3-, 5-, 7-, and 10-year cumulative incidence of progression to advanced fibrosis was 3.6%, 5.0%, 8.2%, and 12.9% in patients without T2DM (n = 1077) and 6.1%, 10.4%, 16.7%, and 24.0% in patients with T2DM (n = 485) (P < 0.001).

CONCLUSIONS

Type 2 diabetes mellitus is associated with progression to advanced liver fibrosis in middle-aged NAFLD patients, even those with less severe liver fibrosis.

A review of the use of transient elastography in the assessment of fibrosis and steatosis in the post-liver transplant patient

Liver biopsy is considered the gold standard method for diagnosing and staging liver disease, particularly in the post-liver transplant setting. Given the invasive nature of biopsy, alternate means for accurately assessing liver fibrosis and steatosis are preferred especially as the number of patients with fatty liver disease is increasing. Transient elastography has been validated as a useful tool for evaluation of liver fibrosis, as has controlled attenuation parameter index as a tool for assessing steatosis. It is a non-invasive, rapid, and highly reproducible approach to demonstrate the presence of fibrosis among non-transplant patients with chronic liver disease of various etiologies. However, it has not yet found wide acceptance in liver transplant recipients. There are few published studies evaluating the merits and applicability of transient elastography to assess allografts after liver transplantation. We review the published data on the use of transient elastography with concurrent controlled attenuation parameter in liver transplant recipients and recommend its greater use to follow allograft function over time.

Apigenin ameliorates HFD-induced NAFLD through regulation of the XO/NLRP3 pathways

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of liver-related morbidity and mortality disease in the world. However, no effective pharmacological treatment for NAFLD has been found. In this study, we used a high fat diet (HFD)-induced NAFLD model to investigate hepatoprotective effect of apigenin (API) against NAFLD and further explored its potential mechanism. Our results demonstrated that gavage administration of API could mitigate HFD-induced liver injury, enhance insulin sensitivity and markedly reduce lipid accumulation in HFD-fed mice livers. In addition, histological analysis showed that hepatic steatosis and macrophages recruitment in the API treatment group were recovered compared with mice fed with HFD alone. Importantly, API could reverse the HFD-induced activation of the NLRP3 inflammasome, further reduced inflammatory cytokines IL-1β and IL-18 release, accompanied with the inhibition of xanthine oxidase (XO) activity and the reduction of uric acid and reactive oxygen species (ROS) production. The pharmacological role of API was further confirmed using free fatty acid (FFA) induced cell NAFLD model. Taking together, our results demonstrated that API could protect against HFD-induced NAFLD by ameliorating hepatic lipid accumulation and inflammation. These protective effects may be partially attributed to the regulation of XO by API, which further modulated NLRP3 inflammasome activation and inflammatory cytokines IL-1β and IL-18 release. Therefore API is a potential therapeutic agent for the prevention of NAFLD.

Dual Energy Transfer-Based Fluorescent Nanoprobe for Imaging miR-21 in Nonalcoholic Fatty Liver Cells with Low Background

Nonalcoholic fatty liver disease (NAFLD) can progress gradually to liver failure, early warning of which is critical for improving the cure rate of NAFLD. In situ imaging and monitoring of overexpressed miR-21 is an advanced strategy for NAFLD diagnosis. However, this strategy usually suffers from the high background imaging in living cells owing to the complexity of the biological system. To overcome this problem, herein, we have developed a one-donor-two-acceptor nanoprobe by assembling gold nanoparticles (AuNPs) coupled with BHQ2 (AuBHQ) and quantum dots (QDs) through DNA hybridization for imaging of miR-21 in living cells. The fluorescence of QDs was quenched up to 82.8% simultaneously by the AuNPs and the BHQ2 via nanometal surface energy transfer and fluorescence resonance energy transfer, reducing the background signals for target imaging. This low background fluorescent nanoprobe was successfully applied for imaging the target miR-21 in nonalcoholic fatty liver cells by catalyzing the disassembly of QDs with the AuBHQ and the fluorescence recovery of QDs. In addition, the sensitivity of this nanoprobe has also been enhanced toward detecting miR-21 in the range of 2.0-15.0 nM with the detection limit (LOD, 3σ) of 0.22 nM, which was 13.5 times lower than that without BHQ2. The proposed approach provides a new way for early warning, treatments, and prognosis of NAFLD.

High prevalence of non-alcoholic fatty liver disease and metabolic risk factors in Guatemala: A population-based study

BACKGROUND

There are no data on the prevalence of non-alcoholic fatty liver disease (NAFLD) in general population samples in Guatemala or in other Central American countries. The prevalence and distribution of NAFLD and its associated risk factors were evaluated in a population-based sample of adults in Guatemala.

METHODS

Cross-sectional study of 411 men and women 40 years of age or older residing in urban and rural areas of Guatemala. Metabolic outcomes included obesity, central obesity, hypercholesterolemia, diabetes, and metabolic syndrome (MetS). Liver disease outcomes included elevated liver enzymes, elevated Fatty Liver Index (FLI), and elevated FIB-4 score.

RESULTS

The overall prevalence of obesity, central obesity, diabetes, and MetS were 30.9, 74.3, 21.6, and 64.2%, respectively. The fully-adjusted prevalence ratios (95% CI) for obesity, central obesity, diabetes, and MetS comparing women to men were 2.83 (1.86-4.30), 1.72 (1.46-2.02), 1.18 (1.03-1.34), and 1.87 (1.53-2.29), respectively. The overall prevalence of elevated liver enzymes (ALT or AST), elevated FLI, and elevated FIB-4 scores were 38.4, 60.1, and 4.1%, respectively. The fully-adjusted prevalence ratios (95% CI) for elevated liver enzymes (either ALT or AST) and elevated FLI score comparing women to men were 2.99 (1.84-4.86) and 1.47 (1.18-1.84), respectively.

CONCLUSIONS

The prevalence of metabolic abnormalities and liver outcomes in this general population study was very high. The prevalence of metabolic and liver abnormalities was particularly high among women, an observation that could explain the atypical 1:1 male to female ratio of liver cancer in Guatemala.

Glyoxalase 1 Modulation in Obesity and Diabetes

Significance: Obesity and type 2 diabetes mellitus are increasing globally. There is also increasing associated complications, such as non-alcoholic fatty liver disease (NAFLD) and vascular complications of diabetes. There is currently no licensed treatment for NAFLD and no recent treatments for diabetic complications. New approaches are required, particularly those addressing mechanism-based risk factors for health decline and disease progression. Recent Advances: Dicarbonyl stress is the abnormal accumulation of reactive dicarbonyl metabolites such as methylglyoxal (MG) leading to cell and tissue dysfunction. It is a potential driver of obesity, diabetes, and related complications that are unaddressed by current treatments. Increased formation of MG is linked to increased glyceroneogenesis and hyperglycemia in obesity and diabetes and also down-regulation of glyoxalase 1 (Glo1)-which provides the main enzymatic detoxification of MG. Glo1 functional genomics studies suggest that increasing Glo1 expression and activity alleviates dicarbonyl stress; slows development of obesity, related insulin resistance; and prevents development of diabetic nephropathy and other microvascular complications of diabetes. A new therapeutic approach constitutes small-molecule inducers of Glo1 expression-Glo1 inducers-exploiting a regulatory antioxidant response element in the GLO1 gene. A prototype Glo1 inducer, trans-resveratrol (tRES)-hesperetin (HESP) combination, in corrected insulin resistance, improved glycemic control and vascular inflammation in healthy overweight and obese subjects in clinical trial. Critical Issues: tRES and HESP synergize pharmacologically, and HESP likely overcomes the low bioavailability of tRES by inhibition of intestinal glucuronosyltransferases. Future Directions: Glo1 inducers may now be evaluated in Phase 2 clinical trials for treatment of NAFLD and vascular complications of diabetes.

A review and critique of published real-world weight management program studies

BACKGROUND

Beyond the essential but somewhat artificial conditions that typify formal clinical studies, real-world evidence (RWE) of weight loss program effectiveness is paramount for an accurate assessment of such programs and refinement of best practices.

OBJECTIVES

To evaluate the current state of RWE studies and publications on weight loss, identify the range of weight loss components being used in RWE programs, and to provide a general overview of the consistency or lack of consistency with regard to measuring and reporting outcomes.

METHODS

A structured search of PubMed was performed to identify relevant English-language publications from 2006 to December 2017 that reported real-world studies of weight loss among adults. Duplicates, non-relevant publications, articles on weight loss surgery, pediatric studies, randomized controlled trials, studies with self-reported weight loss, no objective weight measures, or that failed to include weight loss results were excluded.

RESULTS

This review included 62 RWE publications. Forty-nine studies included dietary intervention, 37 included exercise, 29 included motivational counseling, and 5 contained some patients who had pharmacologic treatment as part of their weight loss regimen. The numbers of participants per study ranged from 10 to more than 3 million. The interventions reported in the publications included diet, exercise, counseling to promote diet and/or exercise, motivational counseling, and pharmacotherapy, and various combinations of these.

CONCLUSIONS

Despite general acceptance that weight loss programs are capable of facilitating successful outcomes, this review revealed substantial inconsistency in the design and reporting of such programs, making it very difficult to draw conclusions about the comparative merits of different real-world weight loss strategies/components. In addition, there was a marked lack of congruence with current weight loss management guidelines, and notably few studies incorporating anti-obesity medications. There clearly is a need for greater rigor and standardization among designing and reporting RWE weight-loss studies.

Impact of controlled attenuation parameter on detecting fibrosis using liver stiffness measurement

BACKGROUND

Liver fibrosis is often accompanied by steatosis, particularly in patients with non-alcoholic fatty liver disease (NAFLD), and its non-invasive characterisation is of utmost importance. Vibration-controlled transient elastography is the non-invasive method of choice; however, recent research suggests that steatosis may influence its diagnostic performance. Controlled Attenuation Parameter (CAP) added to transient elastography enables simultaneous assessment of steatosis and fibrosis.

AIM

To determine how to use CAP in interpreting liver stiffness measurements.

METHODS

This is a secondary analysis of data from an individual patient data meta-analysis on CAP. The main exclusion criteria for the current analysis were unknown aetiology, unreliable elastography measurement and data already used for the same research question. Aetiology-specific liver stiffness measurement cut-offs were determined and used to estimate positive and negative predictive values (PPV/NPV) with logistic regression as functions of CAP.

RESULTS

Two thousand and fifty eight patients fulfilled the inclusion criteria (37% women, 18% NAFLD/NASH, 42% HBV, 40% HCV, 51% significant fibrosis ≥ F2). Youden optimised cut-offs were only sufficient for ruling out cirrhosis (NPV of 98%). With sensitivity and specificity-optimised cut-offs, NPV for ruling out significant fibrosis was moderate (70%) and could be improved slightly through consideration of CAP. PPV for significant fibrosis and cirrhosis were 68% and 55% respectively, despite specificity-optimised cut-offs for cirrhosis.

CONCLUSIONS

Liver stiffness measurement values below aetiology-specific cut-offs are very useful for ruling out cirrhosis, and to a lesser extent for ruling out significant fibrosis. In the case of the latter, Controlled Attenuation Parameter can improve interpretation slightly. Even if cut-offs are very high, liver stiffness measurements are not very reliable for ruling in fibrosis or cirrhosis.

MEASUREMENT OF CONTROLLED ATTENUATION PARAMETER: A SURROGATE MARKER OF HEPATIC STEATOSIS IN PATIENTS OF NONALCOHOLIC FATTY LIVER DISEASE ON LIFESTYLE MODIFICATION - A PROSPECTIVE FOLLOW-UP STUDY

ABSTRACT BACKGROUND: Liver biopsy is a gold standard method for hepatic steatosis assessment. However, liver biopsy is an invasive and painful procedure and can cause severe complications therefore it cannot be frequently used in case of follow-up of patients. Non-invasive assessment of steatosis and fibrosis is of growing relevance in non-alcoholic fatty liver disease (NAFLD). To evaluate hepatic steatosis, transient elastography with controlled attenuation parameter (CAP) measurement is an option now days. OBJECTIVE: Aim of this study is to evaluate role of measurement of controlled attenuation parameter, a surrogate marker of hepatic steatosis in patients of nonalcoholic fatty liver disease on lifestyle modification. METHODS: In this study, initially 37 participants were included who were followed up after 6 months with transient elastography, blood biochemical tests and anthropometric measurements. The results were analyzed by Multivariate linear regression analysis and paired samples t-test (Dependent t-test) with 95% confidence interval. Correlation is calculated by Pearson correlation coefficients. RESULTS: Mean CAP value for assessing hepatic steatosis during 1st consultation (278.57±49.13 dB/m) was significantly improved (P=0.03) after 6 months of lifestyle modification (252.91±62.02 dB/m). Only fasting blood sugar (P=0.008), weight (P=0.000), body mass index (BMI) (P=0.000) showed significant positive correlation with CAP. Only BMI (P=0.034) and weight (P=0.035) were the independent predictor of CAP value in NAFLD patients. CONCLUSION: Lifestyle modification improves the hepatic steatosis, and CAP can be used to detect the improvement of hepatic steatosis during follow-up in patients with NAFLD on lifestyle modification. There is no relation between CAP and Fibroscan score in NAFLD patients. Only BMI and weight can predict CAP value independently.

Targeting ATP-Citrate Lyase in Hyperlipidemia and Metabolic Disorders

Chronic overnutrition and a sedentary lifestyle promote imbalances in metabolism, often manifesting as risk factors for life-threating diseases such as atherosclerotic cardiovascular disease (ASCVD) and nonalcoholic fatty liver disease (NAFLD). Nucleocytosolic acetyl-coenzyme A (CoA) has emerged as a central signaling node used to coordinate metabolic adaptations in response to a changing nutritional status. ATP-citrate lyase (ACL) is the enzyme primarily responsible for the production of extramitochondrial acetyl-CoA and is thus strategically positioned at the intersection of nutrient catabolism and lipid biosynthesis. Here, we discuss recent findings from preclinical studies, as well as Mendelian and clinical randomized trials, demonstrating the importance of ACL activity in metabolism, and supporting its inhibition as a potential therapeutic approach to treating ASCVD, NAFLD, and other metabolic disorders.

Coexistent End-stage Nonalcoholic Steatohepatitis and Colon Cancer: Should We Do Liver Transplantation?

BACKGROUND

Colon cancer accompanying decompensated liver cirrhosis is a rare clinical condition. Usually, treatment of colon cancer is prioritized, with cirrhosis dealt with later.

CASE REPORT

We present a case of end-stage liver disease due to nonalcoholic steatohepatitis evaluated for living donor liver transplant. During the pretransplant examination, an ascending colon cancer was detected. Liver function was too poor to perform colon resection first. Simultaneous living donor liver transplant and colonic resection were carried out. The patient developed left lung metastasis at 2 different times during the first postoperative year, and both of them were resected. The patient received the standard chemoradiotherapy. Now, the patient is alive at 42 months postprocedure and recurrence-free at 31 months postoperatively.

CONCLUSION

Simultaneous liver transplantation and colon resection are possible with acceptable long-term outcomes. Immunosuppressive therapy after transplantation increases the risk for cancer recurrence. So the patient should undergo close surveillance.

Thiazolidinedione drugs in the treatment of type 2 diabetes mellitus: past, present and future

Thiazolidinedione (TZD) drugs used in the treatment of type 2 diabetes mellitus (T2DM) have proven effective in improving insulin sensitivity, hyperglycemia, and lipid metabolism. Though well tolerated by some patients, their mechanism of action as ligands of peroxisome proliferator-activated receptors (PPARs) results in the activation of several pathways in addition to those responsible for glycemic control and lipid homeostasis. These pathways, which include those related to inflammation, bone formation, and cell proliferation, may lead to adverse health outcomes. As treatment with TZDs has been associated with adverse hepatic, cardiovascular, osteological, and carcinogenic events in some studies, the role of TZDs in the treatment of T2DM continues to be debated. At the same time, new therapeutic roles for TZDs are being investigated, with new forms and isoforms currently in the pre-clinical phase for use in the prevention and treatment of some cancers, inflammatory diseases, and other conditions. The aims of this review are to provide an overview of the mechanism(s) of action of TZDs, a review of their safety for use in the treatment of T2DM, and a perspective on their current and future therapeutic roles.

Apigenin, a modulator of PPARγ, attenuates HFD-induced NAFLD by regulating hepatocyte lipid metabolism and oxidative stress via Nrf2 activation

Lipid metabolic disorders and oxidative stress in the liver are key steps in the progression of nonalcoholic fatty liver disease (NAFLD), which is a major risk factor for the development of metabolic syndrome. To date, no pharmacological treatment for this condition has been approved. Our previous study has found that the food-derived compound apigenin (Api) significantly attenuates obesity-induced metabolic syndrome by acting as a peroxisome proliferator-activated receptor gamma modulator (PPARM). Herein, a high fat diet (HFD) induced NAFLD model was used to dig out whether Api had the effect on NAFLD. The results showed that Api had obvious effect in restraining NAFLD progression, including attenuating HFD induced lipid accumulation and oxidative stress in vivo. As a PPARM, although Api did significantly inhibit the expression of PPARγ target genes encoding the protein associated with lipid metabolism, it had no obvious activating effect on PPARγ. Interestingly, we found that Api promoted Nrf2 into the nucleus, thereby markedly activating Nrf2 to inhibit the lipid metabolism related genes and increase the oxidative stress related genes. Further Nrf2 knockdown/knockout and overexpression experiments showed that Api regulating PPARγ target genes was dependent on Nrf2 activation and the activation of Nrf2 counteracted the activation effect of PPARγ by Api. Importantly, we also found that Api might bind with Nrf2 via auto dock and ITC assay. Therefore, our results indicate that Api ameliorates NAFLD by a novel regulating mode of Nrf2 and PPARγ in inhibiting lipid metabolism and oxidative stress abnormity.

Nonalcoholic steatohepatitis in morbid obese patients: coffee consumption vs. disease severity

INTRODUCTION

Obesity correlates with nonalcoholic fatty liver disease (NAFLD) and occurs in 90 to 100% of severely obese individuals (body mass index [BMI] > 35 kg/m2). Coffee consumption (CC) has been associated with reduced progression of fibrosis in both hepatitis C infection and NAFLD; however, this topic is still under discussion when this liver disease affects severely obese individuals.

OBJECTIVE

To assess the association between CC, insulin resistance (IR) and histological NAFLD morbid obese patients.

MATERIAL AND METHODS

Cross-sectional study, including obese individuals undergoing bariatric surgery, liver biopsy and histological diagnosis between September 2013 and August 2014. The patients were classified into 3 groups according to their weekly CC: 0- 239.9 mL; 240-2099.9 mL and ≥ 2100 mL.

RESULTS

A total of 112 obese individuals were included (BMI = 41.9 ± 4.3 kg/m2), with a mean age of 34.7 ± 7.4 years; 68.6% were women. CC was reported by 72.3% of patients. There were no statistical significant differences between groups regarding the presence of IR (84.8% vs. 74.2% vs. 75.9%; p = 0.536). Progressively higher percentages of individuals with normal liver histology were observed (14.7% vs. 21.9% vs. 24.3%). NASH (65.7% vs. 70.3% vs. 57.5%) were observed among those who consumed greater coffee volumes (p = 0.812). In conclusion, obese individuals with elevated CC exhibited lower frequencies of NASH, although with no statistical significance in this sample.

Therapies in non-alcoholic steatohepatitis (NASH)

The hallmark of non-alcoholic fatty liver disease (NAFLD) is excessive fatty accumulation in the hepatocytes, which may be an isolated event (non-alcoholic fatty liver, NAFL) or accompanied by evidence of inflammation and cell injury with or without fibrosis (non-alcoholic steatohepatitis, NASH). NASH, the more aggressive form of NAFLD, may progress to cirrhosis and hepatocellular carcinoma. Since NASH is estimated to overtake hepatitis C virus infection as the leading cause of liver transplantation in the US in the coming decade, and there are no current FDA-approved therapies for this disease, the need to find appropriate therapeutic targets is now more urgent than ever before. Diet and other lifestyle modifications have always been difficult to maintain and this approach alone has not slowed the rising tide of the disease. While the results of traditional therapies such as vitamin E and pioglitazone have been significant for steatosis and inflammation, they have had no effect on fibrosis, which is the strongest indicator of mortality in this condition. However, the understanding of the pathogenesis and progression of NASH has evolved and several promising novel therapies to target and possibly reverse fibrosis are being evaluated, making the future outlook of NASH therapy more optimistic.

Thiazolidinediones for nonalcoholic steatohepatitis: A meta-analysis of randomized clinical trials

The findings regarding the effects of thiazolidinediones (TZDs) in nonalcoholic steatohepatitis (NASH) patients have been inconsistent, and the assessment of different clinical variables for evaluating the effects of TZDs confound a direct comparison of the results of different randomized clinical trials (RCTs), especially with regard to lifestyle changes. In this paper, we performed a meta-analysis of randomized controlled trials to clarify the effects of TZD treatment with and without lifestyle changes on histological markers of NASH and clinical variables related to insulin resistance (IR), hyperlipidemia, and obesity. We searched the literature using the following MeSH terms: "nonalcoholic steatohepatitis," "non-alcoholic steatohepatitis," "thiazolidinedione," "pioglitazone," "rosiglitazone," "randomized," and "clinical trial." Five eligible RCTs were selected, in which patients were treated with either pioglitazone or rosiglitazone, with or without lifestyle changes. We compared the effects of TZD treatment on hepatic fibrosis, lobular inflammation, IR improvement, fasting serum insulin, adiposity, and dyslipidemia between the various studies using fixed and random effects models, and heterogeneity in clinical outcomes was assessed. Significant improvement in hepatic fibrosis did not occur among the patients treated with TZDs alone or in those who underwent both lifestyle changes and TZD therapy. Lobular inflammation decreased in NASH patients who received TZD treatment and in those who underwent both TZD therapy and lifestyle changes. Although TZD treatment resulted in no significant improvement in IR, NASH patients who underwent both lifestyle changes and TZD therapy experienced a significantly greater reduction in their fasting insulin level than that observed in the control patients, whereas patients treated with TZDs alone did not. Although TZD-treated patients experienced significantly greater weight gain than the control patients, TZD treatment had no significant impact on body-mass index, percentage of body fat, or serum levels of cholesterol and triglyceride. Our findings indicate that additional variables should be assessed to obtain a more comprehensive evaluation of the effects of TZD treatment on IR and comorbidity risk factors in NASH patients, and suggest that including lifestyle changes and additional insulin-sensitizing agents in TZD regimens might improve the benefits of TZD therapy for NASH.

Herbal medicines and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), which is characterized by excessive fat accumulation in the liver of patients who consume little or no alcohol, becomes increasingly common with rapid economic development. Long-term excess fat accumulation leads to NAFLD and represents a global health problem with no effective therapeutic approach. NAFLD is considered to be a series of complex, multifaceted pathological processes involving oxidative stress, inflammation, apoptosis, and metabolism. Over the past decades, herbal medicines have garnered growing attention as potential therapeutic agents to prevent and treat NAFLD, due to their high efficacy and low risk of side effects. In this review, we evaluate the use of herbal medicines (including traditional Chinese herbal formulas, crude extracts from medicinal plants, and pure natural products) to treat NAFLD. These herbal medicines are natural resources that can inform innovative drug research and the development of treatments for NAFLD in the future.

Epidemiology and natural history of non-alcoholic fatty liver disease

Non-alcoholic steatohepatitis (NASH) is part of the spectrum of non-alcoholic fatty liver disease (NAFLD) that leads to progressive liver disease and presents a growing challenge to public health. Because of the increased prevalence of metabolic syndrome and obesity, NAFLD and NASH have expanded to a substantial extent. In NASH patients, advanced fibrosis is the major predictor of morbidity and liver-related mortality, and an accurate diagnosis of NASH is mandatory. Although there is currently no validated test of serum biomarkers available to diagnose NASH, and histologic evaluation with a liver biopsy remains the gold standard, screening for fibrosis is recommended in patients with suspicion of NASH. Clinical prediction models and serum biomarkers for advanced fibrosis have relatively good negative predictive value and can be useful for screening. Also, transient elastography is increasingly available to estimate fibrosis in NASH. Therefore, due to the lack of a reliable and accepted non-invasive diagnostic modality, screening for NASH in the general population is not currently recommended. Better understanding of the natural history of NASH is needed to evaluate the utility and cost-effectiveness of screening.

Dicarbonyl stress in clinical obesity

The glyoxalase system in the cytoplasm of cells provides the primary defence against glycation by methylglyoxal catalysing its metabolism to D-lactate. Methylglyoxal is the precursor of the major quantitative advanced glycation endproducts in physiological systems - arginine-derived hydroimidazolones and deoxyguanosine-derived imidazopurinones. Glyoxalase 1 of the glyoxalase system was linked to anthropometric measurements of obesity in human subjects and to body weight in strains of mice. Recent conference reports described increased weight gain on high fat diet-fed mouse with lifelong deficiency of glyoxalase 1 deficiency, compared to wild-type controls, and decreased weight gain in glyoxalase 1-overexpressing transgenic mice, suggesting a functional role of glyoxalase 1 and dicarbonyl stress in obesity. Increased methylglyoxal, dicarbonyl stress, in white adipose tissue and liver may be a mediator of obesity and insulin resistance and thereby a risk factor for development of type 2 diabetes and non-alcoholic fatty liver disease. Increased methylglyoxal formation from glyceroneogenesis on adipose tissue and liver and decreased glyoxalase 1 activity in obesity likely drives dicarbonyl stress in white adipose tissue increasing the dicarbonyl proteome and related dysfunction. The clinical significance will likely emerge from on-going clinical evaluation of inducers of glyoxalase 1 expression in overweight and obese subjects. Increased transcapillary escape rate of albumin and increased total body interstitial fluid volume in obesity likely makes levels of glycation of plasma protein unreliable indicators of glycation status in obesity as there is a shift of albumin dwell time from plasma to interstitial fluid, which decreases overall glycation for a given glycemic exposure.

Visceral adiposity is associated with an increased risk of functional dyspepsia

BACKGROUND

The relationship between visceral adiposity and the incidence of functional dyspepsia (FD) has not yet been studied. The purpose of the present study is to evaluate the association between visceral adiposity and the risk of FD.

METHODS

This is a case-control study that compares the abdominal adipose tissue area between subjects with FD and control subjects without FD, who underwent abdomen computerized tomography (CT) for health examinations in a tertiary center. Retrospectively, a telephone survey was conducted to diagnose FD using the Rome III criteria. We measured various indices of obesity including body mass index (BMI), waist circumference (WC), visceral adipose tissue (VAT) area, subcutaneous adipose tissue (SAT) area and the VAT/SAT ratio in order to evaluate the association between FD and abdominal adiposity.

KEY RESULTS

A total of 363 subjects were included in the present study. FD was diagnosed in 90 subjects (24.8%). In the univariate analysis, WC, VAT area, TAT area, VAT/SAT ratio, and the presence of erosive esophagitis were significantly higher in the FD group than in the non-FD group. In the multivariate analysis, a higher VAT area (odds ratio (OR), 3.76; 95% confidence interval (CI), 1.24-11.40; highest quartile vs lowest quartile, p = 0.019) and VAT/SAT ratio (OR, 2.35; 95% CI, 1.27-4.32; highest quartile vs lowest quartile, p = 0.006) were independently associated with a risk of FD.

CONCLUSION AND INFERENCES

Visceral adiposity as measured by the VAT area and VAT/SAT ratio is associated with an increased risk of FD.

Incretin-based therapies for the treatment of non-alcoholic fatty liver disease: A systematic review and meta-analysis

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease in Western societies. Despite its significance, there are no well-proven pharmacological treatments. Two novel classes of potential pharmacotherapies are the glucagon-like peptide-1 receptor agonists (GLP-1 RA) and dipeptidyl peptidase-4 inhibitors (DPP-4I), collectively known as incretin-based therapies. These have several metabolic and anti-inflammatory actions that may be of benefit in NAFLD. The aim of this meta-analysis was to evaluate their efficacy via a structured retrieval and pooled analysis of relevant studies.

METHODS

Studies were sourced from electronic databases and meeting abstracts. Main inclusion criteria were original studies investigating treatment of adults with NAFLD using GLP-1 RA/DPP-4I. Key outcomes were a change in serum alanine transaminase (ALT), as a marker of liver inflammation, and improvement in disease status measured by imaging or histology.

RESULTS

Initial searching retrieved 1357 peer-reviewed articles and abstracts. Four studies met all inclusion and exclusion criteria. There were a total of 136 participants with NAFLD and concomitant type 2 diabetes mellitus (T2DM). Meta-analysis (random-effects model) revealed a significant decrease in serum ALT following treatment (mean reduction 14.1 IU/L, 95% confidence intervals [CI] 8.3-19.8, P < 0.0001). In two studies with imaging and tissue data, treatment was found to significantly reduce steatosis, inflammation, and fibrosis.

CONCLUSION

The significant decrease in a key biochemical marker of hepatic inflammation following treatment with incretin-based therapies, as well as improvements in imaging and histology, suggests these agents may be effective options for managing NAFLD with comorbid T2DM.

Economic and Quality-of-Life Implications of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a very common chronic liver disease worldwide, is on the rise following the trend of increasing prevalence of obesity, is the second most common indication for liver transplantation, and is an important cause for hepatocellular carcinoma. Despite the increasing recognition of NAFLD as an important chronic liver disease, little has been published on the economic and health-related quality of life (HR-QOL) impact of NAFLD. We reviewed the current literature related to the economics and HR-QOL of NAFLD and found that increased costs and decreased HR-QOL were associated with NAFLD.

Evaluation of Transient Elastography, Acoustic Radiation Force Impulse Imaging (ARFI), and Enhanced Liver Function (ELF) Score for Detection of Fibrosis in Morbidly Obese Patients

BACKGROUND

Liver fibrosis induced by non-alcoholic fatty liver disease causes peri-interventional complications in morbidly obese patients. We determined the performance of transient elastography (TE), acoustic radiation force impulse (ARFI) imaging, and enhanced liver fibrosis (ELF) score for fibrosis detection in bariatric patients.

PATIENTS AND METHODS

41 patients (median BMI 47 kg/m2) underwent 14-day low-energy diets to improve conditions prior to bariatric surgery (day 0). TE (M and XL probe), ARFI, and ELF score were performed on days -15 and -1 and compared with intraoperative liver biopsies (NAS staging).

RESULTS

Valid TE and ARFI results at day -15 and -1 were obtained in 49%/88% and 51%/90% of cases, respectively. High skin-to-liver-capsule distances correlated with invalid TE measurements. Fibrosis of liver biopsies was staged as F1 and F3 in n = 40 and n = 1 individuals. However, variations (median/range at d-15/-1) of TE (4.6/2.6-75 and 6.7/2.9-21.3 kPa) and ARFI (2.1/0.7-3.7 and 2.0/0.7-3.8 m/s) were high and associated with overestimation of fibrosis. The ELF score correctly classified 87.5% of patients.

CONCLUSION

In bariatric patients, performance of TE and ARFI was poor and did not improve after weight loss. The ELF score correctly classified the majority of cases and should be further evaluated.

MicroRNAs in obesity-associated disorders

The emergence of a worldwide obesity epidemic has dramatically increased the prevalence of insulin resistance and metabolic syndrome, predisposing individuals to a greater risk for the development of non-alcoholic fatty liver disease, type II diabetes and atherosclerotic cardiovascular diseases. Current available pharmacological interventions combined with diet and exercise-based managements are still poorly effective for weight management, likely in part due to an incomplete understanding of regulatory mechanisms and pathways contributing to the systemic metabolic abnormalities under disturbed energy homeostasis. MicroRNAs, small non-coding RNAs that regulate posttranscriptional gene expression, have been increasingly described to influence shifts in metabolic pathways under various obesity-related disease settings. Here we review recent discoveries of the mechanistic role that microRNAs play in regulating metabolic functions in liver and adipose tissues involved in obesity associated disorders, and briefly discusses the potential candidates that are being pursued as viable therapeutic targets.

Predictive accuracy of single- and multi-slice MRI for the estimation of total visceral adipose tissue in overweight to severely obese patients

The quantification of visceral adipose tissue (VAT) is increasingly being considered for risk assessment and treatment monitoring in obese patients, but is generally time-consuming. The goals of this work were to semi-automatically segment and quantify VAT areas of MRI slices at previously proposed anatomical landmarks and to evaluate their predictive power for whole-abdominal VAT volumes on a relatively large number of patients. One-hundred and ninety-seven overweight to severely obese patients (65 males; body mass index, 33.3 ± 3.5 kg/m(2); 132 females; body mass index, 34.3 ± 3.2 kg/m(2)) underwent MRI examination. Total VAT volumes (VVAT-T ) of the abdominopelvic cavity were quantified by retrospective analysis of two-point Dixon MRI data (active-contour segmentation, visual correction and histogram analysis). VVAT-T was then compared with VAT areas determined on one or five slices defined at seven anatomical landmarks (lumbar intervertebral spaces, umbilicus and femoral heads) and corresponding conversion factors were determined. Statistical measures were the coefficients of variation and standard deviations σ1 and σ5 of the difference between predicted and measured VAT volumes (Bland-Altman analysis). VVAT-T was 6.0 ± 2.0 L (2.5-11.2 L) for males and 3.2 ± 1.4 L (0.9-7.7 L) for females. The analysis of five slices yielded a better agreement than the analysis of single slices, required only a little extra time (4 min versus 2 min) and was substantially faster than whole-abdominal assessment (24 min). Best agreements were found at intervertebral spaces L3-L4 for females (σ5/1 = 523/608 mL) and L2-L3 for males (σ5/1 = 613/706 mL). Five-slice VAT volume estimates at the level of lumbar disc L3-L4 for females and L2-L3 for males can be obtained within 4 min and were a reliable predictor for abdominopelvic VAT volume in overweight to severely adipose patients. One-slice estimates took only 2 min and were slightly less accurate. These findings may contribute to the implementation of analytical methods for fast and reliable (routine) estimation of VAT volumes in obese patients.

Spontaneous bacterial peritonitis: The clinical challenge of a leaky gut and a cirrhotic liver

Spontaneous bacterial peritonitis (SBP) is a frequent, life-threatening bacterial infection in patients with liver cirrhosis and ascites. Portal hypertension leads to increased bacterial translocation from the intestine. Failure to eliminate invading pathogens due to immune defects associated with advanced liver disease on the background of genetic predisposition may result in SBP. The efficacy of antibiotic treatment and prophylaxis has declined due to the spread of multi-resistant bacteria. Patients with nosocomial SBP and with prior antibiotic treatment are at a particularly high risk for infection with resistant bacteria. Therefore, it is important to adapt empirical treatment to these risk factors and to the local resistance profile. Rifaximin, an oral, non-absorbable antibiotic, has been proposed to prevent SBP, but may be useful only in a subset of patients. Since novel antibiotic classes are lacking, we have to develop prophylactic strategies which do not induce bacterial resistance. Farnesoid X receptor agonists may be a candidate, but so far, clinical studies are not available. New diagnostic tests which can be carried out quickly at the patient’s site and provide additional prognostic information would be helpful. Furthermore, we need tools to predict antibiotic resistance in order to tailor first-line antibiotic treatment of spontaneous bacterial peritonitis to the individual patient and to reduce mortality.

Noninvasive characterization of graft steatosis after liver transplantation

OBJECTIVE

Liver graft steatosis has not been noninvasively evaluated yet. We therefore characterized liver transplant recipients by transient elastography (TE) and controlled attenuation parameter (CAP) and correlated the results with clinical and genetic risk factors.

METHODS

A total of 204 patients (pretransplant disease: n = 102 nonalcoholic etiology, nonalcoholic liver cirrhosis (non-ALC); n = 102 alcoholic liver disease, ALC; 42% female; median age 57.8 years; median time since transplantation 66 months) underwent ultrasound, TE, CAP, and nonalcoholic fatty liver disease (NAFLD) fibrosis score. Recipient DNA samples were genotyped for patatin-like phospholipase domain-containing protein 3 (PNPLA3) (rs738409) and IL28B (rs8099917, rs12979860) polymorphisms.

RESULTS

Increased hepatic echogenicity at ultrasound was observed in 36% of patients, CAP values >252 and >300 dB/m indicated steatosis and advanced steatosis in 44% and 24% of individuals. Advanced fibrosis (TE >7.9 kPa) was associated with increased CAP results (266 vs. 229 dB/m, p = 0.012). PNPLA3 G-allele carriers had increased CAP values (257 vs. 222 dB/m, p = 0.032), higher liver stiffness (TE 6.4 vs. 5.5 kPa, p = 0.005), and prevalence of diabetes mellitus (40% vs. 22%, p = 0.016). No such association was observed for IL28B polymorphisms. ALC compared to non-ALC patients had higher body mass index (28.1 vs. 25.5 kg/m², p < 0.001), higher prevalence of diabetes mellitus (41% vs. 25%, p = 0.017), and PNPLA3 CG + GG genotype (73% vs. 47%, p = 0.006), and had elevated TE (6.3 vs. 5.4 kPa, p = 0.022), CAP (266 vs. 221 dB/m, p = 0.001), and NAFLD fibrosis score (score -0.5 vs. -1.3, p < 0.001).

CONCLUSION

Modern noninvasive liver graft assessment frequently detects hepatic steatosis, which is associated with graft fibrosis, components of the metabolic syndrome and recipient PNPLA3 rs738409 genotype, especially in ALC patients.

Visceral abdominal obesity is associated with an increased risk of irritable bowel syndrome

OBJECTIVES

There are several studies considering obesity as the risk factor for various lower gastrointestinal symptoms. But the relationship between visceral abdominal obesity and the incidence of irritable bowel syndrome (IBS) is not studied yet. The aim of this study was to investigate the association between visceral adipose tissue (VAT) and the risk of IBS.

METHODS

This is a case-control study comparing the VAT area between subjects with IBS (IBS group) and controls without IBS (non IBS group), who underwent abdomen computerized tomography (CT) for routine health checkup from January 2012 to August 2013 in a health promotion center. A telephone survey was retrospectively conducted to diagnose IBS by Rome III criteria. The association between IBS and abdominal obesity was evaluated by measuring VAT, subcutaneous adipose tissue (SAT), VAT/SAT ratio, body mass index (BMI) and waist circumference (WC).

RESULTS

The prevalence of IBS was 19.9% (67/336) among all enrolled subjects. In the univariate analysis, VAT area, VAT/SAT ratio, waist circumference, the presence of reflux esophagitis and the ratio of females were significantly higher in the IBS group than in the non IBS group. However, a higher BMI or a higher SAT area is not associated with an increased risk of IBS. In the multivariate analysis, a higher VAT area (odds ratio (OR)=9.42, 95% confidence interval (CI): 2.90-30.64, highest tertile vs. lowest tertile, P=0.001), VAT/SAT ratio (OR=10.15, 95% CI: 3.05-33.58, highest tertile vs. lowest tertile, P=0.001) and waist circumference (OR=7.81, 95% CI: 2.13-28.66, highest tertile vs. lowest tertile, P=0.002) were independently associated with a risk of IBS. Only in the IBS-D group, not in the IBS-C, visceral adiposity was associated with an increased risk of IBS.

CONCLUSIONS

Visceral adiposity measured by VAT, VAT/SAT, and waist circumference is associated with an increased risk of IBS, especially of IBS-D. However, neither SAT nor BMI are associated with an increased risk of IBS.

Mechanisms Linking Inflammation to Insulin Resistance

Obesity is now widespread around the world. Obesity-associated chronic low-grade inflammation is responsible for the decrease of insulin sensitivity, which makes obesity a major risk factor for insulin resistance and related diseases such as type 2 diabetes mellitus and metabolic syndromes. The state of low-grade inflammation is caused by overnutrition which leads to lipid accumulation in adipocytes. Obesity might increase the expression of some inflammatory cytokines and activate several signaling pathways, both of which are involved in the pathogenesis of insulin resistance by interfering with insulin signaling and action. It has been suggested that specific factors and signaling pathways are often correlated with each other; therefore, both of the fluctuation of cytokines and the status of relevant signaling pathways should be considered during studies analyzing inflammation-related insulin resistance. In this paper, we discuss how these factors and signaling pathways contribute to insulin resistance and the therapeutic promise targeting inflammation in insulin resistance based on the latest experimental studies.

The clinical features and treatment modality of esophageal neuroendocrine tumors: a multicenter study in Korea

BACKGROUND

Neuroendocrine tumors (NETs) of the esophagus are extremely rare, and few cases have been reported worldwide. Thus, a comprehensive nationwide study is needed to understand the characteristics of and treatment strategy for esophageal NETs.

METHODS

We collected data on esophageal NET patients from 25 hospitals in Korea from 2002-2012. The incidence, location, clinical symptoms, histopathology, treatment response, and the biochemical, radiologic and endoscopic characteristics of esophageal NETs were surveyed.

RESULTS

Among 2,037 NETs arising in different gastrointestinal sites, esophageal NETs were found in 26 cases (1.3%). The mean patient age was 60.12 ± 9.30 years with a 4:1 male predominance. In endoscopic findings, 76.9% (20/26) of NETs were located in the lower third of the esophagus and the mean size was 2.34 ± 1.63 cm. At diagnosis, more than half the patients (15/26, 57.7%) had regional lymph node metastasis or widespread metastasis. Endoscopic resection was conducted in three cases, and in all three of them, lymph node metastasis was not found and tumor size was below 1.0 cm. All tumors were completely removable through endoscopic procedures and there was no recurrence during the follow-up period. Eighteen other patients received an operation, chemotherapy or both. Among them, nine patients (50.0%) expired because of the progression of their cancer or post-operative complications. In Kaplan-Meier survival analysis, only tumor size (more than 2.0 cm) showed prognostic significance (P = 0.045).

CONCLUSIONS

Despite the general assumption that gastrointestinal NETs are benign and slow-growing tumors, the prognosis of advanced esophageal NETs is not favorable.

Damage to enteric neurons occurs in mice that develop fatty liver disease but not diabetes in response to a high-fat diet

BACKGROUND

Disorders of gastrointestinal functions that are controlled by enteric neurons commonly accompany fatty liver disease. Established fatty liver disease is associated with diabetes, which itself induces enteric neuron damage. Here, we investigate the relationship between fatty liver disease and enteric neuropathy, in animals fed a high-fat, high-cholesterol diet in the absence of diabetes.

METHODS

Mice were fed a high-fat, high-cholesterol diet (21% fat, 2% cholesterol) or normal chow for 33 weeks. Liver injury was assessed by hematoxylin and eosin, picrosirius red staining, and measurement of plasma alanine aminotransaminase (ALT). Quantitative immunohistochemistry was performed for different types of enteric neurons.

KEY RESULTS

The mice developed steatosis, steatohepatitis, fibrosis, and a 10-fold increase in plasma ALT, indicative of liver disease. Oral glucose tolerance was unchanged. Loss and damage to enteric neurons occurred in the myenteric plexus of ileum, cecum, and colon. Total numbers of neurons were reduced by 15-30% and neurons expressing nitric oxide synthase were reduced by 20-40%. The RNA regulating protein, Hu, became more concentrated in the nuclei of enteric neurons after high-fat feeding, which is an indication of stress on the enteric nervous system. There was also disruption of the neuronal cytoskeletal protein, neurofilament medium.

CONCLUSIONS & INFERENCES

Enteric neuron loss and damage occurs in animals with fatty liver disease in the absence of glucose intolerance. The enteric neuron damage may contribute to the gastrointestinal complications of fatty liver disease.