A Perspective on Metabolic Syndrome and Nonalcoholic Fatty Liver Disease

Hepatic lipid droplet-associated proteome changes distinguish dietary-induced fatty liver from glucose tolerance in male mice

Fatty liver is characterized by the expansion of lipid droplets (LDs) and is associated with the development of many metabolic diseases. We assessed the morphology of hepatic LDs and performed quantitative proteomics in lean, glucose-tolerant mice compared with high-fat diet (HFD) fed mice that displayed hepatic steatosis and glucose intolerance as well as high-starch diet (HStD) fed mice who exhibited similar levels of hepatic steatosis but remained glucose tolerant. Both HFD- and HStD-fed mice had more and larger LDs than Chow-fed animals. We observed striking differences in liver LD proteomes of HFD- and HStD-fed mice compared with Chow-fed mice, with fewer differences between HFD and HStD. Taking advantage of our diet strategy, we identified a fatty liver LD proteome consisting of proteins common in HFD- and HStD-fed mice, as well as a proteome associated with glucose tolerance that included proteins shared in Chow and HStD but not HFD-fed mice. Notably, glucose intolerance was associated with changes in the ratio of adipose triglyceride lipase to perilipin 5 in the LD proteome, suggesting dysregulation of neutral lipid homeostasis in glucose-intolerant fatty liver. We conclude that our novel dietary approach uncouples ectopic lipid burden from insulin resistance-associated changes in the hepatic lipid droplet proteome.NEW & NOTEWORTHY This study identified a fatty liver lipid droplet proteome and one associated with glucose tolerance. Notably, glucose intolerance was linked with changes in the ratio of adipose triglyceride lipase to perilipin 5 that is indicative of dysregulation of neutral lipid homeostasis.

Alismatis Rhizoma methanolic extract—Effects on metabolic syndrome and mechanisms of triterpenoids using a metabolomic and lipidomic approach

Alismatis rhizoma is a traditional Chinese medicine. Studies have demonstrated that Alismatis rhizoma also has therapeutic effects on metabolic syndrome. However, the pharmacodynamic material basis and mechanism are still unclear. First, UHPLC/Q-Orbitrap MS was used to detect the chemical components of the Alismatis rhizoma extract, and 31 triterpenoids and 2 sesquiterpenes were preliminarily identified. Then, to investigate the mechanism of the Alismatis rhizoma extract on metabolic syndrome, a mouse model of metabolic syndrome induced by high-fructose drinks was established. The results of serum biochemical analysis showed that the levels of TG, TC, LDL-C, and UA after the Alismatis rhizoma extract treatment were markedly decreased. ¹H-NMR was used to conduct non-targeted metabolomics studies. A total of 20 differential metabolites were associated with high-fructose–induced metabolic syndrome, which were mainly correlated with 11 metabolic pathways. Moreover, UHPLC/Q-Orbitrap MS lipidomics analysis found that a total of 53 differential lipids were screened out. The results showed that Alismatis rhizoma extract mainly reduces the synthesis of glycerophospholipid and ceramide and improves the secretion of bile acid. This study shows that the Alismatis rhizoma extract can treat metabolic syndrome mainly by inhibiting energy metabolism, amino acid metabolism, and regulating bile acid to reduce phospholipid content.

Non-alcoholic fatty liver disease-related risk of cardiovascular disease and other cardiac complications

BACKGROUND/AIM

Non-alcoholic fatty liver disease (NAFLD) affects approximately 25% of the global adult population. The aim of this narrative review is to describe the associations between NAFLD and cardiovascular disease (CVD), arrhythmias, cardiac conduction defects, myocardial remodelling and heart failure. We also discuss the potential mechanisms that mediate or attenuate the strength of these associations, and briefly summarize the effect of treatments that both ameliorate NAFLD and decrease risk of CVD.

METHODS

Searches of PubMed were performed by the two authors using the terms listed in Appendix. We limited the timeframe to the last decade due to the vast amount of research in the field (up to April 2021) for meta-analyses, reviews and original papers. Only articles published in English were considered.

RESULTS

NAFLD is associated with an increased risk of fatal/non-fatal CVD events and other cardiac and arrhythmic complications (left ventricular hypertrophy, aortic-valve sclerosis and certain arrhythmias), independently of common CVD risk factors. There are probably several underlying mechanisms, including hepatic/systemic insulin resistance, atherogenic dyslipidaemia, hypertension and pro-atherogenic, pro-coagulant and pro-inflammatory mediators released from the steatotic/inflamed liver that may be involved. Some genetic polymorphisms, such as PNPLA3 (rs738409 C>G) and TM6SF2 (rs58542926 C>T), may worsen the liver disease, but also attenuate the strength of the association between NAFLD and CVD, possibly via their effects on lipoprotein metabolism. Of the currently tested drugs for treating NAFLD that also benefit the vasculature, pioglitazone and GLP-1 receptor agonists are the most promising.

CONCLUSIONS

The complex interplay between the liver and cardiometabolic risk factors contributes to CVD, arrhythmias and cardiac disease in NAFLD. There is an urgent need for a multidisciplinary approach to manage both liver disease and cardiometabolic risk, and to test the cardiovascular and cardiac effects of new drugs for NAFLD.

Prediction of Srebp-1 as a Key Target of Qing Gan San Against MAFLD in Rats via RNA-Sequencing Profile Analysis

Metabolism-associated fatty liver disease (MAFLD) is the most common chronic liver disease worldwide, and the use of traditional Chinese medicines (TCMs) to treat this disease has attracted increasing attention. The Qing Gan San (QGS) formula comprises Polygonatum sibiricum, the peel of Citrus reticulata Blanco, the leaves of Morus alba L, Cichorium intybus, Glycyrrhiza uralensis Fisch, and Cirsium setosum. The present study aimed to uncover the anti-hyperlipidaemic effects, hepatic fat accumulation-lowering effects and mechanisms of QGS in high-fat diet-induced MAFLD rats. QGS significantly reduced the levels of total cholesterol and triglycerides in both serum and liver tissue and partially protected hepatic function. Additionally, QGS significantly ameliorated hepatic lipid accumulation with histopathology observation, as demonstrated by H&E and oil red O staining. RNA sequencing was used to further investigate the key genes involved in the development and treatment of MAFLD. Hierarchical clustering analysis showed that the gene expression profiles in rats with MAFLD were reversed to normal after QGS treatment. QGS had 222 potential therapeutic targets associated with MAFLD. Enrichment analysis among these targets revealed that QGS affected biological functions/pathways such as the regulation of lipid metabolic processes (GO: 0019216) and the non-alcoholic fatty liver disease pathway (hsa04932), and identified Srebp-1 as a key regulator in the synthesis of cholesterol and triglycerides. Subsequently, both immunofluorescence and Western blot analyses demonstrated that QGS suppressed the transfer of Srebp-1 to the nucleus from the cytoplasm, suggesting that the activation of Srebp-1 was inhibited. Our study reveals the effects and mechanisms of QGS in the treatment of MAFLD and provides insights and prospects to further explore the pathogenesis of MAFLD and TCM therapies.

Non-alcoholic fatty liver disease: a multisystem disease requiring a multidisciplinary and holistic approach

Non-alcoholic fatty liver disease (NAFLD) is a public health problem worldwide. This narrative Review provides an overview of the current literature to support the notion that NAFLD is a multisystem disease. Convincing evidence shows a strong association between NAFLD and the risk of developing multiple extrahepatic complications such as type 2 diabetes, cardiovascular disease (ie, the predominant cause of mortality in people with NAFLD), chronic kidney disease, and some types of extrahepatic malignancies. The magnitude of this risk parallels the severity of NAFLD (especially the stage of liver fibrosis). There are probably multiple underlying mechanisms by which NAFLD might increase the risk of cardiovascular disease, type 2 diabetes, and extrahepatic complications. Addressing the growing burden of NAFLD will require setting up a multidisciplinary working group and framework to progress and embrace novel collaborative ways of working to deliver holistic, person-centred care and management of people with NAFLD.

Drugs for Non-alcoholic Steatohepatitis (NASH): Quest for the Holy Grail

Nonalcoholic fatty liver disease (NAFLD) is a global epidemic that is likely to become the most common cause of chronic liver disease in the next decade, worldwide. Though numerous drugs have been evaluated in clinical trials, most of them have returned inconclusive results and shown poorly-tolerated adverse effects. None of the drugs have been approved by the Food and Drug Administration for treating biopsy-proven non-alcoholic steatohepatitis (NASH). Vitamin E and pioglitazone have been extensively used in treatment of biopsy-proven nondiabetic NASH patients. Although some amelioration of inflammation has been seen, these drugs did not improve the fibrosis component of NASH. Therefore, dietary modification and weight reduction have remained the cornerstone of treatment of NASH; moreover, they have shown to improve histological activity as well as fibrosis. The search for an ideal drug or 'Holy Grail' within this landscape of possible agents continues, as weight reduction is achieved only in less than 10% of patients. In this current review, we summarize the drugs for NASH which are under investigation, and we provide a critical analysis of their up-to-date results and outcomes.

Nonalcoholic steatohepatitis: the role of peroxisome proliferator-activated receptors

The increasing epidemic of obesity worldwide is linked to serious health effects, including increased prevalence of type 2 diabetes mellitus, cardiovascular disease and nonalcoholic fatty liver disease (NAFLD). NAFLD is the liver manifestation of the metabolic syndrome and includes the spectrum of liver steatosis (known as nonalcoholic fatty liver) and steatohepatitis (known as nonalcoholic steatohepatitis), which can evolve into progressive liver fibrosis and eventually cause cirrhosis. Although NAFLD is becoming the number one cause of chronic liver diseases, it is part of a systemic disease that affects many other parts of the body, including adipose tissue, pancreatic β-cells and the cardiovascular system. The pathomechanism of NAFLD is multifactorial across a spectrum of metabolic derangements and changes in the host microbiome that trigger low-grade inflammation in the liver and other organs. Peroxisome proliferator-activated receptors (PPARs) are a group of nuclear regulatory factors that provide fine tuning for key elements of glucose and fat metabolism and regulate inflammatory cell activation and fibrotic processes. This Review summarizes and discusses the current literature on NAFLD as the liver manifestation of the systemic metabolic syndrome and focuses on the role of PPARs in the pathomechanisms as well as in the potential targeting of disease.

PNPLA3 gene polymorphism is associated with liver steatosis in children with Down syndrome

BACKGROUND AND AIMS

We previously demonstrated that children with Down syndrome (DS) exhibited a greater risk of steatosis than the general pediatric population. This trend was independent of obese phenotype, thus suggesting a role of genetic predisposition. Therefore, we investigated the prevalence of non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS) in function of genetic susceptibility and adipocytokine levels in children with DS.

METHODS AND RESULTS

A total of 84 Caucasian children with DS (age range 5-17 years), were included in this study. For all children, we collected data on anthropometric and biochemical parameters, and liver ultrasound (US). We also measured adipocytokines circulating levels and specific polymorphisms closed to NAFLD. We found a prevalence of 64.3% of liver steatosis at US, with a severe steatosis of about 4% in children with DS. The presence of steatosis in children with DS was associated with the presence of patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 variant, which also correlated with interleukin (IL)-6 levels. Moreover, we found that the 52.4% had a waist circumference > 90th percentile, 21.4% were hypertensive, 7.14% had hyperglycemia, 9.5% had hypertriglyceridemia, and 17.9% showed high-density lipoprotein cholesterol ≤ 40 mg/dl. Finally, the IL-6 and adiponectin levels correlated with steatosis, and several adipocytokines correlated with single MetS traits in children with DS.

CONCLUSION

The present study explores for the first time potential pathomechanisms connecting pediatric NAFLD and MetS in DS. We found that the PNPLA3 variant is associated with steatosis, but not with MetS, in children with DS.

Differential Associations of Circulating MicroRNAs With Pathogenic Factors in NAFLD

Nonalcoholic fatty liver disease (NAFLD) is a heterogeneous disease driven by genetic and environmental factors. MicroRNAs (miRNAs) serve as pleiotropic post‐transcriptional regulators of cellular pathways. Although several miRNAs have been associated with NAFLD and fibrosis, there are limited studies in humans examining their differential association with pathogenic factors or histological features of NAFLD. We examined the differential relationships of five of the best‐described circulating microRNAs (miR‐34a, miR‐122, miR‐191, miR‐192, and miR‐200a) with histological features and pathogenic factors of NAFLD. A cross‐sectional study was conducted to examine the relationship between relative levels of circulating microRNAs standardized by z‐scores and histological features of NAFLD, common NAFLD genetic polymorphisms, and insulin resistance measured by the enhanced lipoprotein insulin resistance index in 132 subjects with biopsy‐proven NAFLD. We found that miR‐34a, miR‐122, miR‐192, miR‐200a, but not miR‐191, strongly correlate with fibrosis in NAFLD by increases of 0.20 to 0.40 SD (P < 0.005) with each stage of fibrosis. In multivariate analysis, miR‐34a, miR‐122, and miR‐192 levels are independently associated with hepatic steatosis and fibrosis, but not lobular inflammation or ballooning degeneration, whereas miR‐200a is only associated with fibrosis. Among the four miRNAs, miR‐34a, miR‐122, and miR‐192 are associated with pathogenic factors of NAFLD, including insulin resistance measured by eLP‐IR, patatin‐like phospholipase domain containing 3 I148M, and transmembrane 6 superfamily 2 (TM6SF2) E167K polymorphisms. In contrast, miR‐200a is only associated with the TM6SF2 E167K variant. Finally, miR‐34a has the strongest predictive value for various stages of fibrosis, with C‐statistic approximates–combined predictive score for miRNAs. Conclusion: miR‐34a, miR‐122, miR‐192, and miR‐200a demonstrate strong associations with NAFLD severity by histology, but differential associations with pathogenic factors.

Noninvasive assessment of hepatic steatosis and fibrosis in patients with severe obesity

PURPOSE

In morbid obesity nonalcoholic fatty liver disease (NAFLD) is endemic. Aim of this study is to evaluate the diagnostic accuracy of the most common noninvasive methods for identify NAFLD and fibrosis in a cohort of morbid obese population.

METHODS

Ninety morbid obese patients undergoing bariatric surgery (BS) and intraoperative liver biopsy were evaluated preoperatively with Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and serum biomarkers for steatosis and fibrosis and liver stiffness measurement (LSM) using acoustic radiation force impulse (ARFI) elastography. All nondiabetic patient (n = 77) underwent OGTT and calculation of Oral Glucose Insulin Sensitivity index (OGIS).

RESULTS

In the entire cohort prevalence of NAFLD was 77%, NASH 24%, moderate/severe steatosis 50%, and significant fibrosis 14%. New cut-offs were evaluated for all steatosis score assessed in this population. In all patients with moderate/severe steatosis HOMA IR was significantly greater than 3.5. ALT, GGT, Triglycerides, HOMA IR, and ARFI increased with fibrosis grade (p 0.03, p 0.008, p 0.04, p 0.05, respectively) and AST to Platelet ratio (APRI) was the only noninvasive fibrosis score significantly increased in significant fibrosis (p 0.04). A combination of 1/OGIS and VAI was able to discriminate NASH from simple steatosis (NAFL) (p 0.02).

CONCLUSIONS

In morbid obese subjects, we calculated new cut-offs of the most common steatosis indexes and found that a score based on insulin resistance (1/OGIS) and abdominal obesity (VAI) could represent a way to identify morbid obese subjects at risk of NASH.

The global epidemiology of NAFLD and NASH in patients with type 2 diabetes: A systematic review and meta-analysis

BACKGROUND & AIMS

Although non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH) and NASH with advanced fibrosis are closely associated with type 2 diabetes mellitus (T2DM), their global prevalence rates have not been well described. Our aim was to estimate the prevalence of NAFLD, NASH, and advanced fibrosis among patients with T2DM, by regions of the world.

METHODS

We searched for terms including NAFLD, NASH and T2DM in studies published from January 1989 to September 2018, using PubMed, Ovid MEDLINE®, EMBASE and Web of Science. Strict exclusion criteria were applied. Regional and global mean prevalence weighted by population size in each country were estimated and pooled using random-effects meta-analysis. Potential sources of heterogeneity were investigated using stratified meta-analysis and meta-regression.

RESULTS

Among 80 studies from 20 countries that met our inclusion criteria, there were 49,419 individuals with T2DM (mean age 58.5 years, mean body mass index 27.9 kg/m², and males 52.9%). The global prevalence of NAFLD among patients with T2DM was 55.5% (95% CI 47.3-63.7). Studies from Europe reported the highest prevalence (68.0% [62.1-73.0%]). Among 10 studies that estimated the prevalence of NASH, the global prevalence of NASH among individuals with T2DM was 37.3% (95% CI 24.7-50.0%). Seven studies estimated the prevalence of advanced fibrosis in patients with NAFLD and T2DM to be 17.0% (95% CI 7.2-34.8). Meta-regression models showed that geographic region and mean age (p <0.5) were associated with the prevalence of NAFLD, jointly accounting for 63.9% of the heterogeneity.

CONCLUSIONS

This study provides the global prevalence rates for NAFLD, NASH, and advanced fibrosis in patients with T2DM. These data can be used to estimate the clinical and economic burden of NASH in patients with T2DM around the world.

LAY SUMMARY

Non-alcoholic fatty liver disease (NAFLD) is now recognized as the most prevalent chronic liver disease worldwide. Type 2 diabetes mellitus (T2DM) is an important risk factor for NAFLD. Additionally, T2DM seems to accelerate the progression of liver disease in NAFLD. Despite the high prevalence and serious clinical implications of NAFLD in patients with T2DM, it is usually overlooked in clinical practice. This meta-analysis provides evidence of the high prevalence of NAFLD and NASH in patients with T2DM. In this context, increasing awareness about the importance of NAFLD in patients with T2DM among all important stakeholders (primary care physicians, specialists, and health policy makers) must be prioritized.

Four-Week Omega-3 Supplementation in Carriers of the Prosteatotic PNPLA3 p.I148M Genetic Variant: An Open-Label Study

BACKGROUND/AIMS

The PNPLA3 loss-of-function variant p.I148M is a strong genetic determinant of nonalcoholic fatty liver disease. The PNPLA3 protein functions as an intracellular lipase in the liver, with a greater activity on unsaturated fatty acids. This study aimed to determine whether short-term supplementation with omega-3 fatty acids impacts hepatic steatosis differently in PNPLA3 p.148I wild-type individuals as compared to homozygous carriers of the PNPLA3 p.148M variant.

METHODS

Twenty subjects with hepatic steatosis (50% women, age 18-77 years) were included. Ten subjects homozygous for the PNPLA3 148M variant were matched to 10 wild-type individuals. The subjects received 4 g omega-3 fatty acids (1,840 mg eicosapentaenoic acid and 1,520 mg docosahexaenoic acid) a day for 4 weeks. Transient elastography with a controlled attenuation parameter (CAP) was used to quantify liver fat before and after the intervention. Body composition, fibrosis, liver function tests, serum free fatty acids (FFA) and glucose markers were compared.

RESULTS

Patients homozygous for the PNPLA3 p.148M variant (risk group) demonstrated no significant changes in CAP compared to baseline (284 ± 55 vs. 287 ± 65 dB/m) as did the control group (256 ± 56 vs. 262 ± 55 dB/m). While serum liver enzyme activities remained unchanged in both groups, the risk group displayed significantly (p = 0.02) lower baseline FFA concentrations (334.5 [range 281.0-431.0] vs. 564.5 [range 509.0-682.0] μmol/L), which markedly increased by 9.1% after the intervention. In contrast, FFA concentrations decreased significantly (p = 0.01) by 28.3% in the wild-type group.

CONCLUSIONS

Short-term omega-3 fatty acid supplementation did not significantly alter hepatic steatosis. The nutrigenomic and metabolic effects of omega-3 fatty acids should be investigated further in carriers of the PNPLA3 148M risk variant.

Prevalence and outcomes of non-alcoholic fatty liver disease (NAFLD) among Asian American adults in the United States

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) affects about 25% of the general population worldwide. Although epidemiology of NAFLD is well studied in the United States, there is paucity of data for the Asian Americans. Our aim was to assess the prevalence and risk factors for NAFLD among Asian Americans.

METHODS

We utilized NHANES data for 2011-2016. We defined NAFLD using recently derived US-FLI. Relative risks (RRs) and population attributable fractions (PAFs) of metabolic components on atherosclerotic cardiovascular disease (ASCVD) and advanced fibrosis were calculated for Asian Americans, and these rates were compared to non-Hispanic whites.

RESULTS

NAFLD prevalence was 18.3% among Asian Americans and 28.4% among non-Hispanic whites. Asian Americans with NAFLD had lower BMI and waist circumference than non-Hispanic whites with NAFLD and were less likely to have metabolic syndrome, cardiovascular disease (CVD), chronic obstructive pulmonary disease, cancer and incident ASCVD (P < 0.05). Hyperlipidaemia had the highest attributable fraction (76.6%) for risk of ASCVD among Asian Americans with NAFLD, followed by diabetes (24.0%), current smoking (9.2%), and obesity (3.7%). Advanced fibrosis in Asian American with NAFLD was independently associated with presence of type 2 diabetes (RR = 2.70, 95% CI: 1.00-7.27).

CONCLUSIONS

Asian Americans have lower prevalence of NAFLD than non-Hispanic whites. However, Asian Americans with NAFLD have similar risk factors for advanced fibrosis and ASCVD than non-Hispanic Whites.

Nutritional and lipidomics biomarkers of docosahexaenoic acid-based multivitamin therapy in pediatric NASH

Two recent randomized controlled trials demonstrated improved radiographic, histological and hepatometabolic cues of non-alcoholic steatohepatitis (NASH) in pediatric patients treated with the ω-3 fatty acid docosahexaenoic acid (DHA) in combination with vitamin D (VD) or with choline (CHO) and vitamin E (VE), the DHA-VD and DHA-CHO-VE trials, respectively). In the present study we verified the nutritional compliance to these DHA-based multivitamin treatments; lipidomics biomarkers of the reported outcome on NASH indicators were also investigated. Samples were obtained from 30 biopsy-proven pediatric NASH patients of the DHA-CHO-VE trial randomized in multivitamin treatment group and placebo group (n = 15 each), and from 12 patients of the treatment group of the DHA-VD trial. All patients underwent 6-month therapy plus 6 months of follow-up. Plasma samples and clinical data were obtained at baseline and at the end of the study (12 months). Selected biomarkers included the free form of DHA and other ω-3 fatty acid arachidonic acid (AA), indices of the vitamin E status, and some hepatic metabolites of these lipids. Radiographic and histological improvements of treated patients were associated with increased concentrations of DHA, α-linolenic acid and α-tocopherol (i.e. VE), and with decreased AA that was also investigated in complex lipids by untargetd lipidomics. As a result a significantly lowered AA/DHA ratio was observed to represent the main indicator of the response to the DHA-based therapy. Furthermore, baseline levels of AA/DHA showed strong association with NAS and US improvement. A stable correction of DHA AA metabolism interaction is associated with the curative effect of this therapy and may represent a key nutritional endpoint in the clinical management of pediatric NASH.

Evaluating feasibility and accuracy of non-invasive tests for nonalcoholic fatty liver disease in severe and morbid obesity

INTRODUCTION

In obese individuals, nonalcoholic fatty liver disease (NAFLD) is common but often goes undiagnosed, and therefore untreated. The presence of significant fibrosis is a key determinant of NAFLD progression, and liver steatosis has substantial cardiovascular implications. We aimed to determine the diagnostic accuracy of common noninvasive diagnostic tests for steatosis and fibrosis in the obese.

METHODS

We recruited 182 severely and morbidly obese individuals undergoing bariatric surgery (age 44 ± 12 years, body mass index 45.1 ± 8.3 kg/m²). Medical history, blood tests and liver biopsy were taken on the day of surgery. Serum steatosis and fibrosis scores were calculated. In a subgroup of patients, transient elastography with controlled attenuation parameter (TE/CAP) (n = 82) and proton magnetic resonance spectroscopy (¹H-MRS) (n = 49) were performed.

RESULTS

¹H-MRS had excellent diagnostic accuracy for steatosis, with strong correlation to steatosis (r = 0.647, p < 0.001), good AUROC (0.852, p = 0.001), sensitivity (81.3%) and specificity (87.5%). However, due to low feasibility in this cohort (65.3% success), this was substantially decreased with intention-to-diagnose analysis (sensitivity 50.0%, specificity 60.9%). CAP had good feasibility (80.5%), and performed better in intention-to-diagnose analysis (AUROC 0.688, sensitivity 84.8%, specificity 47.2%). Serum steatosis scores performed poorly, with comparable accuracy to ALT. For significant fibrosis, TE had the best accuracy (AUROC 0.903, p = 0.007), which remained reasonable after intention-to-diagnose analysis (sensitivity 100%, specificity 59.0%). A combination approach using CAP with ALT for steatosis and TE with Forn index for fibrosis yielded reasonable overall accuracy.

CONCLUSIONS

¹H-MRS and TE/CAP had greatest accuracy for NAFLD-related steatosis and fibrosis. Failure rates in obesity significantly diminished diagnostic ability. Use of a combination of serum and imaging tests improved overall feasibility of assessment and diagnostic accuracy in obese individuals.

The NAFL Risk Score: A simple scoring model to predict 4-y risk for non-alcoholic fatty liver

BACKGROUND

Although several risk factors for non-alcoholic fatty liver (NAFL) have been reported, there are few clinical scores that predict its incidence in the long term. We developed and validate a scoring model for individual prediction of 4-y risk for NAFL.

METHODS

Four-year follow-up data of 8226 initially NAFL-free subjects enrolled for an annual physical examination from Wenzhou Medical Center were analyzed. These subjects are randomly split into the training and the validation cohort. Univariate and multivariable logistic regression models were employed for model development. The selected variables were assigned an integer or half-integer risk score proportional to the estimated coefficient from the logistic model. Risk scores were tested in a validation cohort. We also compared the predictive performance of with that of the NAFLD Index by computing the area under the receiver operating characteristic curve (AUROC).

RESULTS

The NAFL Risk Score was developed as 0 to 18 points comprising of BMI, TG×GGT, ALT/AST, LDL-C/HDL-C and UA in both sexes. Comparison of the observed with the estimated incidence of NAFL at both cohorts showed satisfactory precision. In addition, the NAFL Risk Score showed relatively good discriminative power (AUROC=0.739 for males, 0.823 for females) compared with the NAFLD Index (AUROC=0.661 for males, 0.729 for females) in these Chinese subjects.

CONCLUSIONS

We developed and validated the NAFL Risk Score, a new scoring model to predict 4-y risk for NAFL. The NAFL Risk Score may be clinically simple and useful for assessing individual risk for NAFL.

The Genetic Variant I148M in PNPLA3 Is Associated With Increased Hepatic Retinyl-Palmitate Storage in Humans

CONTEXT

Previous studies revealed that the common sequence variant I148M in patatin-like phospholipase domain-containing protein 3 (PNPLA3) is associated with liver fat content and liver diseases, but not with insulin resistance. Recent data suggest that the PNPLA3 I148M variant has reduced retinyl-palmitate lipase activity in hepatic stellate cells.

OBJECTIVE

We hypothesized that the PNPLA3 I148M variant is associated with elevated retinyl-palmitate storage in human liver as a potential link to the clinical pathology. Design/Setting and Participants: Using HPLC, we quantified the retinoid metabolites in liver tissue extracts obtained from 42 human subjects, including 13 heterozygous and six homozygous carriers of the minor PNPLA3 I148M variant.

MAIN OUTCOME MEASURE

Retinyl-palmitate is elevated in human livers of homozygous PNPLA3 I148M allele carriers Results: The PNPLA3 I148M variant was associated with a significant increase (1.4-fold) in liver fat. The content of retinyl-palmitate was elevated and the ratio of retinol/retinyl-palmitate was reduced in liver extracts obtained from homozygous PNPLA3 I148M minor allele carriers. In a multivariate model including liver fat content, these differences remained significant independent of liver fat content. The content of the minor retinyl-fatty acid esters was similarly increased in homozygous PNPLA3 I148M carriers.

CONCLUSIONS

The increased content of hepatic retinyl-palmitate and the reduced ratio of retinol/retinyl-palmitate in PNPLA3 I148M minor allele carriers support in vitro findings of an altered retinyl-palmitate lipase activity. Our results indicate that the PNPLA3 I148M variant is relevant for the retinyl-palmitate content in human liver, providing a possible link to chronic liver disease.

Omega-3 fatty acids: Mechanisms of benefit and therapeutic effects in pediatric and adult NAFLD

Non-alcoholic fatty liver disease (NAFLD) is currently considered the most common liver disease in industrialized countries, and it is estimated that it will become the most frequent indication for liver transplantation in the next decade. NAFLD may be associated with moderate (i.e. steatosis) to severe (i.e. steatohepatitis and fibrosis) liver damage and affects all age groups. Furthermore, subjects with NAFLD may be at a greater risk of other obesity-related complications later in life, and people with obesity and obesity-related complications (e.g. metabolic syndrome, type 2 diabetes and cardiovascular disease) are at increased risk of developing NAFLD. To date, there is no licensed treatment for NAFLD and therapy has been mainly centered on weight loss and increased physical activity. Unfortunately, it is often difficult for patients to adhere to the advised lifestyle changes. Therefore, based on the known pathogenesis of NAFLD, several clinical trials with different nutritional supplementation and prescribed drugs have been undertaken or are currently underway. Experimental evidence has emerged about the health benefits of omega-3 fatty acids, a group of polyunsaturated fatty acids that are important for a number of health-related functions. Omega-3 fatty acids are present in some foods (oils, nuts and seeds) that also contain omega-6 fatty acids, and the best sources of exclusively omega-3 fatty acids are oily fish, krill oil and algae. In this review, we provide a brief overview of the pathogenesis of NAFLD, and we also discuss the molecular and clinical evidence for the benefits of different omega-3 fatty acid preparations in NAFLD.