Association between metabolic syndrome and the development of non-alcoholic fatty liver disease

High fat in blood and body and increased risk of clinically diagnosed non-alcoholic fatty liver disease in 105,981 individuals

BACKGROUND AND AIMS

High caloric diets rich in fat and carbohydrates lead to increased fat accumulation in adipose tissue and blood. This may lead to increased risk of non-alcoholic fatty liver disease. We hypothesized that baseline high nonfasting plasma triglycerides, body mass index (BMI), and waist circumference, individually and combined, associate with increased risk of clinically diagnosed non-alcoholic fatty liver disease during follow-up.

METHODS

Cohort of 105,981 white Danish individuals recruited in 2003-2015 with end of follow-up on December 13th, 2018. Mean follow-up was 9.2 years during which time 418 were clinically diagnosed at hospitals with non-alcoholic fatty liver disease.

RESULTS

Risk of clinically diagnosed non-alcoholic fatty liver disease increased with higher plasma triglycerides, higher BMI, and with higher waist circumference, continuously and stepwise using multivariable adjusted hazard ratios and cumulative incidences. Combining clinical categories of plasma triglycerides with BMI or waist circumference categories, illustrated an almost additive risk with increasing categories. Compared with plasma triglycerides of <1 mmol/L and BMI <25 kg/m2, the multivariable adjusted hazard ratio was 5.2(95% confidence interval: 1.3-21.6) for individuals with both plasma triglycerides of ≥5 mmol/L and BMI ≥35 kg/m2. The corresponding hazard ratio for individuals with plasma triglycerides ≥5 mmol/L and waist circumference was >88 cm for women and >102 cm for men was 4.8(2.3-9.7). Triglyceride results were more pronounced in women versus men.

CONCLUSIONS

High fat in blood and body measured by plasma triglycerides, BMI, and waist circumference, individually and especially combined, are associated with up to a 5-fold increased risk of clinically diagnosed non-alcoholic fatty liver disease.

Metformin, pioglitazone, dapagliflozin and their combinations ameliorate manifestations associated with NAFLD in rats via anti-inflammatory, anti-fibrotic, anti-oxidant and anti-apoptotic mechanisms

Non-alcoholic fatty liver disease (NAFLD) is an important health threat that is strongly linked to components of metabolic syndrome, particularly the low-grade inflammatory changes. Significantly, several of the available anti-diabetic drug classes demonstrate a considerable anti-inflammatory effect, and hence might be of benefit for NAFLD patients. In this study, we used a rat model of diet-induced NAFLD to examine the potential effect of metformin, pioglitazone, dapagliflozin and their combinations on NAFLD manifestations. Rats were fed an atherogenic diet containing 1.25 % cholesterol, 0.5 % cholic acid and 60 % cocoa butter for 6 weeks causing a number of metabolic and hepatic alterations including insulin resistance, dyslipidemia, systemic inflammation, increased hepatic oxidative stress and lipid peroxidation, hepatic steatosis, lobular inflammation, as well as increased markers of liver inflammation and hepatocyte apoptosis. Drug treatment, which started at the third week of NAFLD induction and continued for three weeks, not only ameliorated the observed metabolic impairment, but also functional and structural manifestations of NAFLD. Specifically, anti-diabetic drug treatment reversed markers of systemic and hepatic inflammation, oxidative stress, hepatic fibrosis, and hepatocyte apoptosis. Our findings propose that anti-diabetic drugs with a potential anti-inflammatory effect can ameliorate the manifestations of NAFLD, and thus may provide a therapeutic option for such a condition that is closely associated with metabolic diseases. The detailed pharmacology of these classes in aspects linked to the observed impact on NAFLD requires to be further investigated and translated into clinical studies for tailored therapy specifically targeting NAFLD.

The Association Between Metabolic Syndrome and Non-Alcoholic Fatty Liver Disease Diagnosis Varies by Race

Objectives: This study investigated how the association between metabolic syndrome (MetS) and nonalcoholic fatty liver disease (NAFLD) diagnosis varies between non-Hispanic African American and white patients. Methods: A retrospective cohort study was performed using electronic medical records from an integrated health care system (2010-2018). Adults with records for all MetS measurements (body mass index, lipids, blood pressure, and blood glucose) in 2011, who did not have a NAFLD diagnosis before their last MetS measurement, were included. Results: The study cohort consisted of 139,336 patients (age 56.1 ± 15.2 years, 57.9% female, 79.4% non-Hispanic white). The rate of NAFLD diagnosis was higher in MetS patients compared with non-MetS patients [adjusted hazards ratio (AHR) = 1.99, 95% CI = 1.91-2.09] with a significant interaction by race (AHR = 2.05, 95% CI = 1.95-2.15 in non-Hispanic whites vs. AHR = 1.76, 95% CI = 1.58-1.96 non-Hispanic African Americans, P = 0.017). Secondary analyses revealed that the relative NAFLD diagnosis rate was higher in non-Hispanic whites with MetS compared with non-Hispanic African Americans with MetS among females and patients 18-39 years of age and 40-59 years, but not among males and those ≥60 years of age. Conclusions: Non-Hispanic white patients with MetS, particularly females and those <60 years of age, may be at increased risk of NAFLD compared with non-Hispanic African American MetS patients and may benefit from extra attention regarding NAFLD screening.

Abelmoschus esculentus subfractions ameliorate hepatic lipogenesis and lipid uptake via regulating dipeptidyl peptidase-4—With improving insulin resistance

Nonalcoholic fatty liver disease (NAFLD) is recognized as the liver component of metabolic syndrome. The regulation of hepatic lipid should be emphasized to prevent accompanying illness. As AMP-activated protein kinase (AMPK) and sterol regulatory element binding protein (SREBP) regulate lipid metabolism, CD36 and fatty acid synthase (FAS) promote lipid uptake and lipogenesis respectively, while acetyl-CoA carboxylase (ACC) is an indicator of negative feedback. The increase of IRS-1 phosphorylation at the residue ser307 (p-ser307-IRS-1) and decrease of p-ser473-Akt (p-Akt) are viewed as the insulin resistance markers, and our previous reports suggested dipeptidyl peptidase-4 (DPP-4) mediates insulin resistance, the crucial factor of metabolic syndrome. Abelmoschus esculentus (AE) fruit is well-known for its antidiabetic utility. We had isolated several AE subfractions by successive steps, and found that F1 and F2 were especially valid in suppressing DPP-4 signaling. Since little is known if AE works on NAFLD, now we first attempt to investigate whether AE is useful to attenuate hepatic lipogenesis and lipid uptake in liver cells, along with improving the metabolic targets. We demonstrated that AE subfractions attenuated the hepatic lipid accumulation induced by free fatty acids. Treatment of AE alleviated FAS and returned the level of p-ser79-ACC (p-ACC). Although F1 was more effective on AMPK, F2 seemed more stable to attenuate SREBP-1. Moreover, as fatty acids stimulated the expression of CD36, F2 showed a superior effect to down-regulate the lipid uptake. Both AE subfractions reduced the generation of ROS, decreased the level of p-ser307-IRS-1, and restored the expression of p-Akt. Moreover, treatment of DPP-4 inhibitor linagliptin revealed that, AE could prevent the hepatic lipogenesis, oxidative burden, and the related insulin resistance via downregulating DPP-4. In conclusion, the present investigation revealed that AE, especially F2, is potential to be developed as adjuvant to prevent NAFLD.

Epidemiology of nonalcoholic fatty liver disease in non-obese populations: Meta-analytic assessment of its prevalence, genetic, metabolic, and histological profiles

OBJECTIVE

As a subgroup of nonalcoholic fatty liver disease (NAFLD), patients with non-obese NAFLD may also have an increased risk of adverse hepatic and metabolic outcomes. We aimed to estimate the prevalence and incidence of non-obese NAFLD and to describe its clinical characteristics in this systematic review and meta-analysis.

METHODS

We performed a systematic search of 1235 citations published up to Mar 2020. Meta-analyses, stratified analyses and meta-regression were all performed.

RESULTS

Of the 46 studies included, 28 cross-sectional and longitudinal studies of 155 846 non-obese participants reported a pooled NAFLD prevalence of 14.5% (95% confidence interval [CI] 12.3%-17.1%). A multivariate meta-regression analysis showed the trend that the prevalence varied by their geographical location. Further stratified analyses showed that NAFLD was relatively prevalent among people aged ≥45 years (16.2%; 95% CI 10.8-23.4) and those in South America (25.7%; 95% CI 24.4-27.0). The PNPLA3 rs738409 gene polymorphism was more frequently observed in non-obese NAFLD than in both obese NAFLD and non-obese controls, while the metabolic profiles of non-obese NAFLD were less severe than those of the obese NAFLD group. Patients with non-obese NAFLD had 4.81-fold and 5.43-fold higher risk of diabetes mellitus and metabolic syndrome, respectively, than the non-obese controls.

CONCLUSIONS

Non-obese NAFLD is common, particularly in South America and among people aged ≥45 years. Metabolic diseases and PNPLA3 rs738409 gene polymorphism are more frequent in the non-obese NAFLD group than in non-obese controls.

Modulation of Glucose Metabolism by Leaf Tea Constituents: A Systematic Review of Recent Clinical and Pre-clinical Findings

Leaf teas are widely used as a purported treatment for dysregulated glucose homeostasis. The objective of this study was to systematically evaluate the clinical and cellular-metabolic evidence, published between January 2013 and May 2019, and indexed on PubMed, ScienceDirect, and Web of Science, supporting the use of leaf teas for this purpose. Fourteen randomized controlled trials (RCTs) (13 on Camellia sinensis teas) were included, with mixed results, and providing scant mechanistic information. In contrast, 74 animal and cell culture studies focusing on the pancreas, liver, muscle, and adipose tissue yielded mostly positive results and highlighted enhanced insulin signaling as a recurring target associated with the effects of teas on glucose metabolism. We conclude that more studies, including RCTs and pre-clinical studies examining teas from a wider variety of species beyond C. sinensis, are required to establish a stronger evidence base on the use of leaf teas to normalize glucose metabolism.

The severity of coronary artery disease was not associated with non-alcoholic fatty liver disease in a series of 264 non-diabetic patients who underwent coronary angiography

BACKGROUND

It is now suggested an association between non-alcoholic fatty liver disease (NAFLD) and the occurrence of coronary artery disease even in non-diabetic patients. We will determine the rate of NAFLD and its main determinants in non-diabetic patients undergoing coronary angiography.

METHODS

This cross-sectional study was accomplished on 264 patients who were candidates for coronary angiography during the year 2016. Coronary angiography has been done to depict the presence or absence of coronary involvement, and the severity of coronary artery disease by determining the number of vessels involved and also the SYNTAX score. During 48 hours after coronary angiography, the patients underwent abdominal ultrasonography for detection of NAFLD.

RESULTS

The overall prevalence of NAFLD in the patients was 72.3%. The prevalence of NAFLD in those with and without coronary involvement was 71.9% and 73.1% respectively, with no notable difference (p = 0.837). The mean SYNTAX score in the patients with and without NAFLD was 22.32 ± 11.10 and 21.75 ± 10.71 respectively with no difference (p = 0.702). According to the multivariable regression models, the presence of NAFLD could not predict the likelihood of coronary artery disease (OR = 0.879, p = 0.669) or its severity assessed by the SYNTAX score (beta = 0.046, p = 0.456). NAFLD grade was also not a determinant for coronary artery disease (OR = 1.139, p = 0.178) or its severity (beta = 0.058, p = 0.165).

CONCLUSION

It seems that the presence and grade of NAFLD may not be correlated with atherosclerotic involvement of coronary arteries and its severity in non-diabetic patients. Future large studies and trials could elucidate the independent role of fatty liver in nondiabetic non-alcoholic patients.

Effect of semaglutide on liver enzymes and markers of inflammation in subjects with type 2 diabetes and/or obesity

BACKGROUND

Obesity and type 2 diabetes are drivers of non-alcoholic fatty liver disease (NAFLD). Glucagon-like peptide-1 analogues effectively treat obesity and type 2 diabetes and may offer potential for NAFLD treatment.

AIM

To evaluate the effect of the glucagon-like peptide-1 analogue, semaglutide, on alanine aminotransferase (ALT) and high-sensitivity C-reactive protein (hsCRP) in subjects at risk of NAFLD.

METHODS

Data from a 104-week cardiovascular outcomes trial in type 2 diabetes (semaglutide 0.5 or 1.0 mg/week) and a 52-week weight management trial (semaglutide 0.05-0.4 mg/day) were analysed. Treatment ratios vs placebo were estimated for ALT (both trials) and hsCRP (weight management trial only) using a mixed model for repeated measurements, with or without adjustment for change in body weight.

RESULTS

Elevated baseline ALT (men >30 IU/L; women >19 IU/L) was present in 52% (499/957) of weight management trial subjects. In this group with elevated ALT, end-of-treatment ALT reductions were 6%-21% (P<0.05 for doses≥0.2 mg/day) and hsCRP reductions 25%-43% vs placebo (P < 0.05 for 0.2 and 0.4 mg/day). Normalisation of elevated baseline ALT occurred in 25%-46% of weight management trial subjects, vs 18% on placebo. Elevated baseline ALT was present in 41% (1325/3268) of cardiovascular outcomes trial subjects. In this group with elevated ALT, no significant ALT reduction was noted at end-of-treatment for 0.5 mg/week, while a 9% reduction vs placebo was seen for 1.0 mg/week (P = 0.0024). Treatment ratios for changes in ALT and hsCRP were not statistically significant after adjustment for weight change.

CONCLUSIONS

Semaglutide significantly reduced ALT and hsCRP in clinical trials in subjects with obesity and/or type 2 diabetes.

The Mexican consensus on nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) affects nearly one third of the population worldwide. Mexico is one of the countries whose population has several risk factors for the disease and its prevalence could surpass 50%. If immediate action is not taken to counteract what is now considered a national health problem, the medium-term panorama will be very bleak. This serious situation prompted the Asociación Mexicana de Gastroenterología and the Asociación Mexicana de Hepatología to produce the Mexican Consensus on Fatty Liver Disease. It is an up-to-date and detailed review of the epidemiology, pathophysiology, clinical forms, diagnosis, and treatment of the disease, whose aim is to provide the Mexican physician with a useful tool for the prevention and management of nonalcoholic fatty liver disease.

Differentially methylated loci in NAFLD cirrhosis are associated with key signaling pathways

Altered DNA methylation events contribute to the pathogenesis and progression of metabolic disorders, including nonalcoholic fatty liver disease (NAFLD). Investigations of global DNA methylation patterns in liver biopsies representing severe NAFLD fibrosis have been limited. We used the HumanMethylation 450K BeadChip to analyze genome-wide methylation in patients with biopsy-proven grade 3/4 NAFLD fibrosis/cirrhosis (N = 14) and age- and sex-matched controls with normal histology (N = 15). We identified 208 CpG islands (CGIs), including 99 hypomethylated and 109 hypermethylated CGIs, showing statistically significant evidence (adjusted P value < 0.05) for differential methylation between cirrhotic and normal samples. Comparison of β values for each CGI to the read count of its corresponding gene obtained from RNA-sequencing analysis revealed negative correlation (adjusted P value < 0.05) for 34 transcripts. These findings provide supporting evidence for a role for CpG methylation in the pathogenesis of NAFLD-related cirrhosis, including confirmation of previously reported differentially methylated CGIs, and contribute new insight into the molecular mechanisms underlying the initiation and progression of liver fibrosis and cirrhosis.

Predictors of Liver Fat and Stiffness in Non-Alcoholic Fatty Liver Disease (NAFLD) - an 11-Year Prospective Study

Liver fat can be non-invasively measured by proton magnetic resonance spectroscopy (¹H-MRS) and fibrosis estimated as stiffness using transient elastography (FibroScan). There are no longitudinal data on changes in liver fat in Europids or on predictors of liver stiffness using these methods. We determined liver fat (¹H-MRS) and clinical characteristics including features of insulin resistance at baseline and after a median follow-up period of 11.3 (range 7.3-13.4) years in 97 Finnish subjects. Liver stiffness was measured at 11.3 years. Liver fat content decreased by 5% (p < 0.05) over time. Values at baseline and 11.3 years were closely interrelated (r = 0.81, p < 0.001). Baseline liver fat (OR 1.32; 95%CI: 1.15-1.50) and change in BMI (OR 1.67; 95%CI: 1.24-2.25) were independent predictors of liver fat at 11.3 years (AUROC 0.90; 95%CI: 0.83-0.96). Baseline liver fat (AUROC 0.84; 95%CI: 0.76-0.92) predicted liver fat at 11.3 years more accurately than routinely available parameters (AUROC 0.76; 95%CI: 0.65-0.86, p = 0.02). At 11.3 years, 29% of the subjects had increased liver stiffness. Baseline liver fat (OR 2.17; 95%CI: 1.05-4.46) was an independent predictor of increased liver stiffness. These data show that liver fat is more important than the associated metabolic abnormalities as the predictor of future liver fat and fibrosis.

Syringaresinol-4-O-β-d-glucoside alters lipid and glucose metabolism in HepG2 cells and C2C12 myotubes

Syringaresinol-4-O-β-d-glucoside (SSG), a furofuran-type lignan, was found to modulate lipid and glucose metabolism through an activity screen of lipid accumulation and glucose consumption, and was therefore considered as a promising candidate for the prevention and treatment of metabolic disorder, especially in lipid and glucose metabolic homeostasis. In this study, the effects of SSG on lipogenesis and glucose consumption in HepG2 cells and C2C12 myotubes were further investigated. Treatment with SSG significantly inhibited lipid accumulation by oil red O staining and reduced the intracellular contents of total lipid, cholesterol and triglyceride in HepG2 cells. No effect was observed on cell viability in the MTT assay at concentrations of 0.1–10 μmol/L. SSG also increased glucose consumption by HepG2 cells and glucose uptake by C2C12 myotubes. Furthermore, real-time quantitative PCR revealed that the beneficial effects were associated with the down-regulation of sterol regulatory element-binding proteins-1c, -2 (SREBP-1c, -2), fatty acid synthase (FAS), acetyl CoA carboxylase (ACC) and hydroxyl methylglutaryl CoA reductase (HMGR), and up-regulation of peroxisome proliferator-activated receptors alpha and gamma (PPARα and PPARγ). SSG also significantly elevated transcription activity of PPARγ tested by luciferase assay. These results suggest that SSG is an effective regulator of lipogenesis and glucose consumption and might be a candidate for further research in the prevention and treatment of lipid and glucose metabolic diseases.

Embrionary way to create a fatty liver in portal hypertension

Portal hypertension in the rat by triple partial portal vein ligation produces an array of splanchnic and systemic disorders, including hepatic steatosis. In the current review these alterations are considered components of a systemic inflammatory response that would develop through three overlapping phenotypes: The neurogenic, the immune and the endocrine. These three inflammatory phenotypes could resemble the functions expressed during embryonic development of mammals. In turn, the inflammatory phenotypes would be represented in the embryo by two functional axes, that is, a coelomic-amniotic axis and a trophoblastic yolk-sac or vitelline axis. In this sense, the inflammatory response developed after triple partial portal vein ligation in the rat would integrate both functional embryonic axes on the liver interstitial space of Disse. If so, this fact would favor the successive development of steatosis, steatohepatitis and fibrosis. Firstly, these recapitulated embryonic functions would produce the evolution of liver steatosis. In this way, this fat liver could represent a yolk-sac-like in portal hypertensive rats. After that, the systemic recapitulation of these embryonic functions in experimental prehepatic portal hypertension would consequently induce a gastrulation-like response in which a hepatic wound healing reaction or fibrosis occur. In conclusion, studying the mechanisms involved in embryonic development could provide key results for a better understanding of the nonalcoholic fatty liver disease etiopathogeny.

The Possible Role of Helicobacter pylori Infection in Non-alcoholic Fatty Liver Disease

Helicobacter pylori (H. pylori) which colonizes the stomach can cause a wide array of gastric disorders, including chronic gastritis, peptic ulcer, and gastric cancer. Recently, accumulating evidence has implicated H. pylori infection in extragastrointestinal diseases such as cardiovascular diseases, neurological disorders, and metabolic diseases. At the same time, many scholars have noted the relationship between H. pylori infection and non-alcoholic fatty liver disease (NAFLD). Despite the positive association between H. pylori and NAFLD reported in some researches, there are opposite perspectives denying their relationship. Due to high prevalence, unclear etiology and difficult treatment of NAFLD, confirming the pathogenicity of H. pylori infection in NAFLD will undoubtedly provide insights for novel treatment strategies for NAFLD. This paper will review the relationship between H. pylori infection and NAFLD and the possible pathogenic mechanisms.

Associations between hemoglobin concentrations and the development of incidental metabolic syndrome or nonalcoholic fatty liver disease

AIMS

Hemoglobin (Hb) is known to be associated with both nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome (MS). We evaluated the relationship between serum Hb levels and the development of MS or NAFLD.

METHODS

A retrospective cohort study was conducted. We recruited participants who underwent abdominal ultrasonography and blood samplings in both 2005 and 2010.

RESULTS

Graded independent relationships were observed between higher Hb levels and the incidence of MS and NAFLD. After adjusting for age, body mass index, and fasting glucose, high-density lipoprotein cholesterol and triglyceride levels, the risk of developing MS was significantly higher according to the Hb quartiles in men (P for trend=0.027). The adjusted odds ratio (OR) and 95% confidence intervals (CIs) for the highest Hb quartile was 1.81 (1.06-3.10) for women and 1.43 (1.00-2.05) for men. The risk of developing NAFLD was also significantly higher according to the Hb quartiles in men (P for trend=0.03). The adjusted OR and 95% CI for the highest Hb quartile was 1.18 (0.73-1.91) in women and 1.76 (1.16-2.66) in men.

CONCLUSIONS

The risk of developing either MS or NAFLD was significantly associated with serum Hb levels in men. These findings have implications in the clinical availability of serum Hb as a predictor of MS and NAFLD.

Obesity is an independent risk factor for non-alcoholic fatty liver disease: evidence from a meta-analysis of 21 cohort studies

BACKGROUND

The association between obesity and nonalcoholic fatty liver disease (NAFLD) has not been fully quantified, and the magnitude of NAFLD risk associated with obesity is still unclear. A meta-analysis of cohort studies was performed to elucidate the NAFLD risk associated with obesity.

METHODS

Pubmed, Web of Science and Embase were searched for cohort studies assessing NAFLD risk associated with obesity or increased body mass index (BMI). Relative risks (RRs) with 95% confidence intervals (95%CIs) were pooled using random-effects model of meta-analysis.

RESULTS

Twenty-one cohort studies including 13 prospective studies and 8 retrospective studies were finally included. There were a total of 381,655 participants in the meta-analysis. Compared with normal weight, obesity independently led to a 3.5-fold increased risk of developing NAFLD (RR = 3.53, 95%CI 2.48 to 5.03, P < 0.001). Meta-analysis also suggested an obvious dose-dependent relationship between BMI and NAFLD risk (per 1-unit increment in BMI: RR = 1.20, 95%CI 1.14 to 1.26, P < 0.001). Subgroup analyses further identified the robustness of the association above. No obvious risk of publication bias was observed.

CONCLUSION

Obese individuals have a 3.5-fold increased risk of developing NAFLD, and there is an obvious dose-dependent relationship between BMI and NAFLD risk. © 2016 World Obesity.

The Metabolic Syndrome and Its Influence on Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) and the metabolic syndrome (MetS) are highly prevalent in the Western population. Their pathogenesis is closely linked to insulin resistance, which serves as a therapeutic target for the management of these conditions. This review article reviews the research supporting the influence of MetS on NASH and includes studies supporting their similar epidemiology, pathogenesis, and treatment.

Bariatric surgery and nonalcoholic fatty liver disease

The rising prevalence of nonalcoholic fatty liver disease (NAFLD) is associated with the increasing global pandemic of obesity. These conditions cluster with type II diabetes mellitus and the metabolic syndrome to result in obesity-associated liver disease. The benefits of bariatric procedures on diabetes and the metabolic syndrome have been recognized for some time, and there is now mounting evidence to suggest that bariatric procedures improve liver histology and contribute to the beneficial resolution of NAFLD in obese patients. These beneficial effects derive from a number of weight-dependent and weight-independent mechanisms including surgical BRAVE actions (bile flow changes, restriction of stomach size, anatomical gastrointestinal rearrangement, vagal manipulation, enteric hormonal modulation) and subsequent effects such as reduced lipid intake, adipocytokine secretion, modulation of gut flora, improvements in insulin resistance and reduced inflammation. Here, we review the clinical investigations on bariatric procedures for NAFLD, in addition to the mounting mechanistic data supporting these findings. Elucidating the mechanisms by which bariatric procedures may resolve NAFLD can help enhance surgical approaches for metabolic hepatic dysfunction and also contribute toward developing the next generation of therapies aimed at reducing the burden of obesity-associated liver disease.

Green tea polyphenol epigallocatechin-3-gallate ameliorates insulin resistance in non-alcoholic fatty liver disease mice

AIM

Epigallocatechin-3-gallate (EGCG) is a major polyphenol in green tea. In this study, we investigated the effects of EGCG on insulin resistance and insulin clearance in non-alcoholic fatty liver disease (NAFLD) mice.

METHODS

Mice were fed on a high-fat diet for 24 weeks. During the last 4 weeks, the mice were injected with EGCG (10, 20 and 40 mg·kg(-1)·d(-1), ip). Glucose tolerance, insulin tolerance and insulin clearance were assessed. After the mice were euthanized, blood samples and tissue specimens were collected. Glucose-stimulated insulin secretion was examined in isolated pancreatic islets. The progression of NAFLD was evaluated histologically and by measuring lipid contents. Insulin-degrading enzyme (IDE) protein expression and enzyme activity were detected using Western blot and immunocapture activity assays, respectively.

RESULTS

The high-fat diet significantly increased the body weight and induced grade 2 or 3 liver fatty degeneration (steatosis, lobular inflammation and ballooning) accompanied by severe hyperlipidemia, hyperglycemia, hyperinsulinemia and insulin resistance in the model mice. Administration of EGCG dose-dependently ameliorated the hepatic morphology and function, reduced the body weight, and alleviated hyperlipidemia, hyperglycemia, hyperinsulinemia and insulin resistance in NAFLD mice. Furthermore, EGCG dose-dependently enhanced insulin clearance and upregulated IDE protein expression and enzyme activity in the liver of NAFLD mice.

CONCLUSION

EGCG dose-dependently improves insulin resistance in NAFLD mice not only by reducing body weight but also through enhancing the insulin clearance by hepatic IDE. The results suggest that IDE be a potential drug target for the treatment of NAFLD.

Severity of non-alcoholic fatty liver disease is associated with high systemic levels of tumor necrosis factor alpha and low serum interleukin 10 in morbidly obese patients

Morbid obesity has been shown to increase the risk to develop hepatic steatosis, also referred to as non-alcoholic fatty liver disease (NAFLD). Emerging evidence suggests that the severity of NAFLD may associate with increased serum levels of inflammatory markers as well as decreased concentration of mediators with anti-inflammatory actions, such as tumor necrosis factor alpha (TNF-α) and interleukin (IL) 10, respectively. We thus examined the serum levels of TNF-α and IL-10 in 102 morbidly obese women and men (body mass index > 40 kg/m(2)), exhibiting different grades of NAFLD. Blood glucose, glycated hemoglobin, insulin, the homeostatic model assessment of insulin resistance (HOMA-IR), total cholesterol, triglycerides, high- and low-density lipoproteins, parameters of liver function, TNF-α, and IL-10 were measured in each subject. The stage of NAFLD was estimated by abdominal ultrasound imaging. In comparison with morbidly obese subjects without steatosis, morbidly obese patients with NAFLD showed increased age (39.23 ± 9.80 years), HOMA-IR (6.74 ± 1.62), total cholesterol (219.7 ± 9.58 mg/dl), aspartate aminotransferase (36.25 ± 3.24 UI/l), gamma-glutamyl transpeptidase (37.12 ± 3.41 UI/l), and TNF-α (37.41 ± 1.72 pg/ml) as well as decreased serum levels of IL-10 (61.05 ± 2.43 pg/ml). Interestingly, the systemic levels of TNF-α increased, while IL-10 decreased in accordance with the severity of NAFLD, which supports a role for systemic inflammatory mediators in promoting steatosis progression. Further clinical prospective studies need to be addressed to elucidate the role of TNF-α and IL-10 in the development of NAFLD while also establishing their clinical utility in the assessment of morbidly obese patients at higher risk to develop severe steatosis.

Genome-wide analysis of hepatic lipid content in extreme obesity

AIMS

Individuals with type 2 diabetes have an increased risk of developing non-alcoholic fatty liver disease (NAFLD), and NAFLD patients are also at greater risk for developing type 2 diabetes. Although the relationship between type 2 diabetes and NAFLD is highly interconnected, the pathogenic mechanisms linking the two diseases are poorly understood. The goal of this study was to identify genetic determinants of hepatic lipid accumulation through association analysis using histological phenotypes in obese individuals.

METHODS

Using the Illumina HumanOmniExpress BeadChip assay, we genotyped 2,300 individuals on whom liver biopsy data were available.

RESULTS

We analyzed total bilirubin levels, which are linked to fatty liver in severe obesity, and observed the strongest evidence for association with rs4148325 in UGT1A (P < 5.0 × 10(-93)), replicating previous findings. We assessed hepatic fat level and found strong evidence for association with rs4823173, rs2896019, and rs2281135, all located in PNPLA3 and rs10401969 in SUGP1. Analysis of liver transcript levels of 20 genes residing at the SUGP1/NCAN locus identified a 1.6-fold change in the expression of the LPAR2 gene in fatty liver. We also observed suggestive evidence for association between low-grade fat accumulation and rs10859525 and rs1294908, located upstream from SOCS2 and RAMP3, respectively. SOCS2 was differentially expressed between fatty and normal liver.

CONCLUSIONS

These results replicate findings for several hepatic phenotypes in the setting of extreme obesity and implicate new loci that may play a role in the pathophysiology of hepatic lipid accumulation.

Hepatitis B virus infection and metabolic syndrome: fact or fiction?

Although hepatitis C virus infection is known to be linked with insulin resistance, dyslipidemia, and hepatic steatosis, the relationship between hepatitis B virus (HBV) infection and metabolic factors remains unclear. HBV infection is a health problem worldwide, especially in endemic regions such as Asia and Africa. It induces liver decompensation, cirrhosis, hepatocellualr carcinoma, and premature mortality. The prevalence of metabolic syndrome continues to increase in parallel with the epidemic of obesity, which is closely associated with the development of diabetes, cardiovascular disease, or even cancer. The systemic review shows that chronic HBV infection protects against instead of promotes fatty liver. The mechanism is possibly due to a lower frequency of dyslipidemia profile in patients with chronic HBV infection. The association of HBV with metabolic syndrome, insulin resistance, and the risk of arteriosclerosis is still inconclusive. In addition, obesity, diabetes, and metabolic syndrome may accelerate the progression of liver disease in patients with chronic HBV infection and synergistically induce cirrhosis or even hepatocellualr carcinoma development.

Thyroid function is associated with non-alcoholic fatty liver disease in euthyroid subjects

OBJECTIVES

This study was designed to test the hypothesis that normal thyroid function is associated with non-alcoholic fatty liver disease (NAFLD) in euthyroid general subjects.

METHODS

A total of 739 euthyroid subjects were enrolled in this cross-sectional study. Using ultrasound, a diagnosis of NAFLD was made in subjects without a history of excessive alcohol consumption or liver diseases. Fasting serum samples were collected for determining thyroid function [thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) levels] and other biochemical parameters.

RESULTS

Among the enrolled subjects, 196 (26.5%) satisfied the diagnostic criteria for NAFLD. Subjects with NAFLD had significantly higher TSH levels and lower FT4 levels than those without NAFLD (p < 0.01 for both). NAFLD prevalence increased gradually with increasing quartiles of TSH levels and decreasing quartiles of FT4 levels. After adjustment for gender and age, TSH levels were found to correlate positively with body mass index (BMI), waist circumference (WC), and LDL-cholesterol levels (p < 0.05 for all) and negatively with HDL-cholesterol levels (p < 0.01). FT4 levels correlated negatively with both BMI and WC (p < 0.05 for both). Multiple logistic regression analysis showed that TSH and FT4 levels were independent risk factors for NAFLD [odds ratio (OR): 2.21, 95% confidence interval (CI): 1.21-4.02, p = 0.01, for TSH levels; OR: 0.39, 95% CI: 0.17-0.87, p = 0.02, for FT4 levels].

CONCLUSION

Our findings suggest that serum FT4 and TSH levels, even those within the reference range, are associated with NAFLD in the general population, independent of known metabolic risk factors.

Physical activity and risk of fatty liver in people with different levels of alcohol consumption: a prospective cohort study

OBJECTIVE

To investigate whether physical activity affects the future incidence of fatty liver in people with never-moderate and heavy alcohol consumption.

DESIGN

Prospective cohort study.

SETTING

Health check-up programme at Meiji Yasuda Shinjuku Medical Center in Shinjuku Ward, Tokyo, Japan.

POPULATION

A total of 10,146 people aged 18 years or older without fatty liver enrolled through baseline surveys conducted from 2005 to 2007. They were grouped into never-moderate alcohol drinkers (n=7803) and heavy alcohol drinkers (n=2343) and followed until 2013.

MAIN OUTCOME MEASURE

Incident fatty liver diagnosed by ultrasound.

RESULTS

During a mean follow-up of 4.4 years (34,648 person-years), 1255 never-moderate alcohol drinkers developed fatty liver; 520 heavy alcohol drinkers developed fatty liver during a mean follow-up of 4.1 years (9596 person-years). For never-moderate alcohol drinkers, engaging in >3×/week of low-intensity (HR=0.82, 95% CI 0.71 to 0.96) and moderate-intensity (HR=0.56, 95% CI 0.39 to 0.81) physical activity significantly reduced incident fatty liver compared with those who engaged in physical activity <1×/week. For vigorous-intensity physical activity, frequencies of 2×/week (HR=0.57, 95% CI 0.38 to 0.86) and >3×/week (HR=0.55, 95% CI 0.38 to 0.79) were significantly associated with lower risk of incident fatty liver. In propensity-adjusted models, these significant associations still remained. By contrast, in heavy alcohol drinkers, there were no significant associations between the type or frequency of physical activity and incident fatty liver.

CONCLUSIONS

Physical activity had an independent protective effect on incident fatty liver only in the never-moderate alcohol drinkers, and the preventive effect increased with higher frequencies and intensities of physical activity.

Management of fatty liver disease with the metabolic syndrome

Non-alcoholic fatty liver disease (NAFLD) is the liver disease of this century, increasing in parallel with obesity, insulin resistance and the metabolic syndrome. NAFLD can be seen as a component of the metabolic syndrome, and as such, contributing as a risk factor for cardiovascular disease. In fact, these patients die more often from cardiovascular disease than from direct consequences of liver disease. In this review, we will summarize the data that link NAFLD as a central player in this dysmetabolism, as well as the evidence for appropriate therapy, in order to improve not only liver disease prognosis, but also the overall prognosis and risk of mortality, with particular focus on cardiovascular risk.

Non-alcoholic fatty liver disease in patients with migraine

Evidence suggests that migraine is associated with metabolic syndrome, which is also implicated in non-alcoholic fatty liver disease (NAFLD). Reported for the first time, we aimed to investigate the relationship between migraine and NAFLD in patients with migraine. A total of 90 consecutive migraine patients were enrolled in this cross-sectional study. The diagnosis of migraine was determined according to the International Classification of Headache Disorders-II diagnostic criteria. The diagnosis of NAFLD was based on abdominal ultrasonography findings. Anthropometric indices and the homeostasis model assessment of insulin resistance (HOMA-IR) were calculated, and serum insulin level measurements and other biochemical analyses were performed for each subject. The measurements of body mass index and waist circumference were significantly higher in migraine patients with NAFLD than in those without NAFLD (p < 0.001). Regarding the laboratory results, insulin (p = 0.024), alanine aminotransferase (p = 0.027), and triglyceride levels (p = 0.001) and the HOMA-IR (p = 0.039) were higher in migraineurs with NAFLD than in those without NAFLD. Among the headache characteristics, the presence of aura was higher, and disease and attack durations were significantly longer in migraineurs with NAFLD than in those without NAFLD (p = 0.005, p = 0.024, and p = 0.023; respectively). However, the headache characteristics did not correlate with either the hepatosteatosis grade or HOMA-IR in migraine patients (p > 0.05). Our results show that NAFLD may present in migraine patients with higher frequency of auras and longer disease and attack durations.

Identification of novel clinical factors associated with hepatic fat accumulation in extreme obesity

OBJECTIVES

The accumulation of lipids stored as excess triglycerides in the liver (steatosis) is highly prevalent in obesity and has been associated with several clinical characteristics, but most studies have been based on relatively small sample sizes using a limited set of variables. We sought to identify clinical factors associated with liver fat accumulation in a large cohort of patients with extreme obesity.

METHODS

We analyzed 2929 patients undergoing intraoperative liver biopsy during a primary bariatric surgery. Univariate and multivariate regression modeling was used to identify associations with over 200 clinical variables with the presence of any fat in the liver and with moderate to severe versus mild fat accumulation.

RESULTS

A total of 19 data elements were associated with the presence of liver fat and 11 with severity of liver fat including ALT and AST, plasma lipid, glucose, and iron metabolism variables, several medications and laboratory measures, and sleep apnea. The accuracy of a multiple logistic regression model for presence of liver fat was 81% and for severity of liver fat accumulation was 77%.

CONCLUSIONS

A limited set of clinical factors can be used to model hepatic fat accumulation with moderate accuracy and may provide potential mechanistic insights in the setting of extreme obesity.

Analysis of NHANES 1999-2002 data reveals noteworthy association of alcohol consumption with obesity

BACKGROUND

With the obesity pandemic sweeping the globe and alcohol use on the rise worldwide, there is growing interest in how the two might be linked epidemiologically. The aim of the study was to use data from the NHANES registry from 1999-2002 to analyze the association between obesity and alcohol use.

METHODS

Multivariate logistic regression was used to assess the relationship between alcohol use and obesity. Risk was assessed separately for men and women.

RESULTS

Of the 9,193 individuals (49% males), 26.8% of males and 33.6% of females were obese. About 17% of males and 12% of females were never drinkers (less than 12 drinks in their lifetime). After adjusting for age, race, marital status, highest level of education of the individual and spouse, country of origin, annual household income and duration of physical activity in the past 30 days, the odds of obesity were higher in never drinkers compared to ever drinkers in both men and women. Consumption of alcohol for more than 45 days, binge drinking (>5 drinks/day) for more than 90 days and being "ever binge drinker" were associated with significantly higher odds of obesity (in both genders) than those who drank for shorter duration or were "never binge drinkers". Consumption of alcohol more than the recommended limit for moderate drinking (3 drinks/day in females and 4 drinks/day in males) was associated with increased (OR 1.074, 95% CI 1.072-1.076) and decreased (OR 0.970, 95%CI 0.968-0.972) obesity in females and males respectively.

CONCLUSION

Frequent or heavy alcohol consumption is associated with greater odds of being obese.

Nonalcoholic Fatty liver: a possible new target for type 2 diabetes prevention and treatment

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder worldwide. Several lines of evidence have indicated a pathogenic role of insulin resistance, and a strong association with type 2 diabetes (T2MD) and metabolic syndrome. Importantly, NAFLD appears to enhance the risk for T2MD, as well as worsen glycemic control and cardiovascular disease in diabetic patients. In turn, T2MD may promote NAFLD progression. The opportunity to take into account NAFLD in T2MD prevention and care has stimulated several clinical studies in which antidiabetic drugs, such as metformin, thiazolidinediones, GLP-1 analogues and DPP-4 inhibitors have been evaluated in NAFLD patients. In this review, we provide an overview of preclinical and clinical evidences on the possible efficacy of antidiabetic drugs in NAFLD treatment. Overall, available data suggest that metformin has beneficial effects on body weight reduction and metabolic parameters, with uncertain effects on liver histology, while pioglitazone may improve liver histology. Few data, mostly preclinical, are available on DPP4 inhibitors and GLP-1 analogues. The heterogeneity of these studies and the small number of patients do not allow for firm conclusions about treatment guidelines, and further randomized, controlled studies are needed.