Current concepts in the pathogenesis of nonalcoholic fatty liver disease

Hepatic and Pancreatic Cellular Response to Early Life Nutritional Mismatch

To determine the basis for perinatal nutritional mismatch causing metabolic dysfunction-associated steatotic liver disease and diabetes mellitus, we examined adult phenotype, hepatic transcriptome, and pancreatic β-islet function. In prenatal caloric-restricted rats with intrauterine growth restriction (IUGR) and postnatal exposure to high fat with fructose (HFhf) or high carbohydrate, we investigated male and female IUGR-HFhf and IUGR-high carbohydrate, vs HFhf and control offspring. Males more than females displayed adiposity, glucose intolerance, insulin resistance, hyperlipidemia, and hepatomegaly with hepatic steatosis. Male hepatic triglyceride synthesis, de novo lipogenesis genes increased, while female lipolysis, β-oxidation, fatty acid efflux, and FGF21 genes increased. IUGR-HFhf males demonstrated reduced β-islet insulin and humanin, and type 1 diabetes mellitus human amniotic fluid increased humanin. Humanin suppression disabled glucose stimulated insulin, ATP production, with apoptotic diminished β-islet viability. Humanin and FGF21 may reverse perinatal nutritional mismatched phenotype by restoring functional β islets and preventing metabolic dysfunction-associated steatotic liver disease and diabetes mellitus.

(E)-5-hydroxy-7-methoxy-3-(2-hydroxybenzyl)-4-chromanone, a Major Homoisoflavonoid, Attenuates Free Fatty Acid-Induced Hepatic Steatosis by Activating AMPK and PPARα Pathways in HepG2 Cells

BACKGROUND

(E)-5-hydroxy-7-methoxy-3-(2-hydroxybenzyl)-4-chromanone (HMC), a homoisoflavonoid isolated from Portulaca oleracea, has significant anti-adipogenesis potential; it regulates adipogenic transcription factors. However, whether HMC improves hepatic steatosis in hepatocytes remains vague. This study investigated whether HMC ameliorates hepatic steatosis in free fatty acid-treated human hepatocellular carcinoma (HepG2) cells, and if so, its mechanism of action was analyzed.

METHODS

Hepatic steatosis was induced by a free fatty acid mixture in HepG2 cells. Thereafter, different HMC concentrations (10, 30, and 50 µM) or fenofibrate (10 µM, a PPARα agonist, positive control) was treated in HepG2 cells.

RESULTS

HMC markedly decreased lipid accumulation and triglyceride content in free fatty acid-treated HepG2 cell; it (10 and 50 μM) markedly upregulated protein expressions of pAMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase. HMC (10 and 50 μM) markedly inhibited the expression of sterol regulatory element-binding protein-1c, fatty acid synthase, and stearoyl-coA desaturase 1, which are the enzymes involved in lipid synthesis. Furthermore, HMC (10 and 50 μM) markedly upregulated the protein expression of peroxisome proliferator-activated receptor alpha (PPARα) and enhanced the protein expressions of carnitine palmitoyl transferase 1 and acyl-CoA oxidase 1.

CONCLUSION

HMC inhibits lipid accumulation and promotes fatty acid oxidation by AMPK and PPARα pathways in free fatty acid-treated HepG2 cells, thereby attenuating hepatic steatosis.

Dose-response relationship of serum ferritin and dietary iron intake with metabolic syndrome and non-alcoholic fatty liver disease incidence: a systematic review and meta-analysis

Aim

This study aims to assess the dose-response impact of iron load on systemic and hepatic metabolic disorders including metabolic syndrome (MetS) and non-alcoholic fatty liver disease (NAFLD).

Methods

Serum ferritin (SF) and dietary iron intake were selected to represent the indicators of iron load in the general population. PubMed, EMBASE and Web of Science databases were searched for epidemiological studies assessing the impact of SF/dietary iron intake on MetS/NAFLD occurrence. All literature was published before September 1st, 2023 with no language restrictions.

Results

Fifteen and 11 papers were collected with a focus on connections between SF and MetS/NAFLD, respectively. Eight papers focusing on dietary iron and MetS were included in the following meta-analysis. For the impact of SF on MetS, the pooled odds ratio (OR) of MetS was 1.88 (95% CI: 1.58-2.24) for the highest versus lowest SF categories. In males, the OR was 1.15 (95% CI: 1.10-1.21) per incremental increase in SF of 50 μg/L, while for females, each 50 μg/L increase in SF was associated with a 1.50-fold higher risk of MetS (95% CI: 1.15-1.94). For connections between SF and NAFLD, we found higher SF levels were observed in NAFLD patients compared to the control group [standardized mean difference (SMD) 0.71; 95% CI: 0.27-1.15], NASH patients against control group (SMD1.05; 95% CI:0.44-1.66), NASH patients against the NAFLD group (SMD 0.6; 95% CI: 0.31-1.00), each 50 μg/L increase in SF was associated with a 1.08-fold higher risk of NAFLD (95% CI: 1.07-1.10). For the impact of dietary iron on MetS, Pooled OR of MetS was 1.34 (95% CI: 1.10-1.63) for the highest versus lowest dietary iron categories.

Conclusion

Elevated SF levels is a linear relation between the incidence of MetS/NAFLD. In addition, there is a positive association between dietary iron intake and metabolic syndrome. The association between serum ferritin and metabolic syndrome may be confounded by body mass index and C-reactive protein levels.

The effects of grape seed extract supplementation on cardiovascular risk factors, liver enzymes and hepatic steatosis in patients with non-alcoholic fatty liver disease: a randomised, double-blind, placebo-controlled study

BACKGROUND

Despite the high antioxidant potential of grape seed extract (GSE), very limited studies have investigated its effect on non-alcoholic fatty liver disease (NAFLD). Therefore, this study was conducted with the aim of investigating the effect of GSE on metabolic factors, blood pressure and steatosis severity in patients with NAFLD.

METHODS

In this double-blind randomized clinical trial study, 50 NAFLD patients were divided into two groups of 25 participants who were treated with 520 mg/day of GSE or the placebo group for 2 months. The parameters of glycemic, lipid profile, blood pressure and steatohepatitis were measured before and after the intervention.

RESULTS

The GSE group had an average age of 43.52 ± 8.12 years with 15 women and 10 men, while the placebo group had an average age of 44.88 ± 10.14 years with 11 women and 14 men. After 2 months of intervention with GSE, it was observed that insulin, HOMA-IR, TC, TG, LDL-c, ALT, AST, AST/ALT, SBP, DBP and MAP decreased and QUICKi and HDL-c increased significantly (p-value for all < 0.05). Also, before and after adjustment based on baseline, the average changes indicated that the levels of insulin, HOMA-IR, TC, TG, LDL-c, SBP, DBP, MAP in the GSE group decreased more than in the control group (p for all < 0.05). Furthermore, the changes in HDL-c were significantly higher in the GSE group (p < 0.05). The between-groups analysis showed a significant decrease in the HOMA-β and AST before and after adjustment based on baseline levels (p < 0.05). Moreover, the changes in QUICKi after adjustment based on baseline levels were higher in the GSE group than in the control group. Also, between-groups analysis showed that the severity of hepatic steatosis was reduced in the intervention group compared to the placebo group (P = 0.002).

CONCLUSIONS

It seems that GSE can be considered one of the appropriate strategies for controlling insulin resistance, hyperlipidemia, hypertension and hepatic steatosis in NAFLD patients.

TRIAL REGISTRATION

The clinical trial was registered in the Iranian Clinical Trial Registration Center (IRCT20190731044392N1). https://irct.behdasht.gov.ir/trial/61413 . (The registration date: 30/03/2022).

Does myo-inositol supplementation influence oxidative stress biomarkers in patients with non-alcoholic fatty liver disease?

Myo-inositol (MI) is a carbocyclic sugar polyalcohol. MI has known to exert anti-inflammatory, anti-oxidant, and anti-diabetic activities. This study aimed to investigate the effects of MI supplementation on oxidative stress biomarkers in obese patients with non-alcoholic fatty liver disease (NAFLD). In this double-blinded placebo-controlled randomized clinical trial, 51 newly diagnosed obese patients with NAFLD were randomly assigned to receive either MI (4 g/day) or placebo supplements accompanied by dietary recommendations for 8 weeks. Oxidative stress biomarkers, nutritional status, as well as liver enzymes and obesity indices were assessed pre- and post-intervention. A total of 48 patients completed the trial. Although anthropometric measures and obesity indices decreased significantly in both groups, the between-group differences adjusted for confounders were non-significant for these parameters, except for weight (p = .049); greater decrease was observed in the MI group. Iron and zinc intakes decreased significantly in both groups; however, between-group differences were non-significant at the end of the study. No significant between-group differences were revealed for other antioxidant micronutrients at the study endpoint. Sense of hunger, feeling to eat, desire to eat sweet and fatty foods reduced significantly in both groups (p < .05), while the feeling of satiety increased significantly in the placebo group (p = .002). No significant between-group differences were observed for these parameters, except for desire to eat fatty foods; a greater decrease was observed in the MI group (p = .034). Serum levels of glutathione peroxidase (GPx) and superoxide dismutase (SOD) significantly increased in both study groups (p < .05); however, the between-group differences were non-significant at the end of the study. Furthermore, the between-group differences were non-significant for other oxidative stress biomarkers, except for serum nitric oxide (NO) level; a greater decrease was observed in the MI group. MI supplementation could significantly improve weight, desire to eat fatty foods, serum levels of NO, as well as the aspartate aminotransferase (AST)/ALT ratio.

The triglycerides and glucose index is highly associated with non-alcoholic fatty liver disease in overweight and obese women

BACKGROUND

Although some previous studies have indicated that the triglycerides and glucose (TyG) index is associated with an increased risk of non-alcoholic fatty liver disease (NAFLD), there are still few studies in this field.

AIMS

The goal of this study was to assess whether the TyG index is associated with the presence of non-alcoholic fatty liver disease NAFLD in overweight and obese women.

METHODS

Overweight and obese women aged 20 to 65 years were enrolled in a cross-sectional study and allocated into the groups with and without NAFLD. Alcohol consumption, pregnancy, normal-weight, positive markers of viral or autoimmune hepatitis, acute or chronic liver disease, renal disease, cardiovascular disease, neoplasia, and intake of hepatotoxic drugs were exclusion criteria. The diagnosis of NAFLD was established by liver ultrasound and the TyG index was calculated as the Ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)]/2.

RESULTS

A total of 420 participants were enrolled and allocated into the groups with (n = 212) and without (n = 208) NAFLD. In the overall population, the frequency of NAFLD was 50.4%. The logistic regression analysis adjusted by body mass index, waist circumference, and total body fat showed that total cholesterol (OR = 1.004; 95% CI: 1.000-1.007), triglycerides (OR = 1.002; 95% CI: 1.000-1.004), AST (OR = 1.19; 95% CI: 1.15-1.23), ALT (OR = 1.20; 95% CI: 1.15-1.25), and TyG index (OR = 3.15; 95% CI: 1.64-6.06) are significantly associated with NAFLD.

CONCLUSIONS

The results show that the TyG index is highly associated with the presence of NAFLD in women with overweight and obesity.

Macrophages and the development and progression of non-alcoholic fatty liver disease

The liver is the site of first pass metabolism, detoxifying and metabolizing blood arriving from the hepatic portal vein and hepatic artery. It is made up of multiple cell types, including macrophages. These are either bona fide tissue-resident Kupffer cells (KC) of embryonic origin, or differentiated from circulating monocytes. KCs are the primary immune cells populating the liver under steady state. Liver macrophages interact with hepatocytes, hepatic stellate cells, and liver sinusoidal endothelial cells to maintain homeostasis, however they are also key contributors to disease progression. Generally tolerogenic, they physiologically phagocytose foreign particles and debris from portal circulation and participate in red blood cell clearance. However as immune cells, they retain the capacity to raise an alarm to recruit other immune cells. Their aberrant function leads to the development of non-alcoholic fatty liver disease (NAFLD). NAFLD refers to a spectrum of conditions ranging from benign steatosis of the liver to steatohepatitis and cirrhosis. In NAFLD, the multiple hit hypothesis proposes that simultaneous influences from the gut and adipose tissue (AT) generate hepatic fat deposition and that inflammation plays a key role in disease progression. KCs initiate the inflammatory response as resident immune effectors, they signal to neighbouring cells and recruit monocytes that differentiated into recruited macrophages in situ. Recruited macrophages are central to amplifying the inflammatory response and causing progression of NAFLD to its fibro-inflammatory stages. Given their phagocytic capacity and their being instrumental in maintaining tissue homeostasis, KCs and recruited macrophages are fast-becoming target cell types for therapeutic intervention. We review the literature in the field on the roles of these cells in the development and progression of NAFLD, the characteristics of patients with NAFLD, animal models used in research, as well as the emerging questions. These include the gut-liver-brain axis, which when disrupted can contribute to decline in function, and a discussion on therapeutic strategies that act on the macrophage-inflammatory axis.

Comparative study of dietary fat: lard and sugar as a better obesity and metabolic syndrome mice model

BACKGROUND

Diet macronutrient heterogeneity hinders animal studies' data extrapolation from metabolic disorders to human diseases.

OBJECTIVE

The present study aimed to evaluate different fat-diet compositions' effect on inducing lipid/glucose metabolism alterations in mice.

METHODS

Swiss male mice were fed for 12 weeks with five different diets: Standard Diet (ST), American Institute of Nutrition 93 for growth (AIN93G) high-butter/high-sugar (HBHS), high-lard/high-sugar (HLHS), and high-oil/high-sugar diet (soybean oil) (HOHS). Several parameters, such as serum biochemistry, histology, and liver mRNA expression, were accessed.

RESULTS

The main findings revealed that the HLHS diet dramatically altered liver metabolism inducing hepatic steatosis and increased total cholesterol, triglycerides, VLDL, increasing liver CCAAT/enhancer binding protein (CEBP-α), Acetyl-CoA carboxylase (ACC) and Catalase (CAT) mRNA expression. Moreover, the HLHS diet increased glucose intolerance and reduced insulin sensitivity.

CONCLUSIONS

High-fat/high-sugar diets are efficient to induce obesity and metabolic syndrome-associated alterations, and diets enriched with lard and sugar showed more effective results.

Prevalence of nonalcoholic fatty liver disease and the related risk factors among healthy adults: A cross-sectional study in Chongqing, China

Background

Epidemiological characteristics of nonalcoholic fatty liver disease (NAFLD) in Chongqing, a west-central city of China, remain unclear. The objective of this study was to investigate the prevalence of NAFLD and the related risk factors among healthy adults for physical examination in Chongqing.

Methods

A total of 110,626 subjects were enrolled in the present study. Each of the participants underwent physical examination, laboratory measurements, and abdominal ultrasonography. The chi-square test was employed to compare differences in the NAFLD prevalence, and logistic regression analysis was used to estimate the odds ratio for risk factors of NAFLD.

Results

The prevalence of NAFLD in individuals in the population of Chongqing was 28.5%, and the prevalence in men (38.1%) was significantly higher than that in women (13.6%) (OR = 2.44; 95% CI: 2.31-2.58). NAFLD was more common in men aged 51-60 years and women over 60 years. Approximately 79.1% of the people with obesity and 52.1% of the people with central obesity had NAFLD. The prevalence of NAFLD in people with hypertension and cholelithiasis was 48.9 and 38.4%, respectively. Logistic regression showed that gender, age, body max index (BMI), central obesity, hypertension, impaired fasting glucose/diabetes mellitus (DM), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), hyperuricemia (HUA), alanine transaminase (ALT), and cholelithiasis were independently associated with the presence of NAFLD.

Conclusion

The prevalence of NAFLD among healthy adults in Chongqing was high. To improve the prevention and management of NAFLD, special attention should be paid to the factors associated with the presence of NAFLD, including higher BMI, higher waist circumference, higher blood glucose, hypertension, hypertriglyceridemia, hyperuricemia, cholelithiasis, and elevated ALT.

Beneficial effects of Lactobacillus rhamnosus hsryfm 1301 fermented milk on rats with nonalcoholic fatty liver disease

A growing stream of research suggests that probiotic fermented milk has a good effect on nonalcoholic fatty liver disease. This work aimed to study the beneficial effects of Lactobacillus rhamnosus hsryfm 1301 fermented milk (fermented milk) on rats with nonalcoholic fatty liver disease induced by a high-fat diet. The results showed that the body weight and the serum levels of total cholesterol, total glyceride, low-density lipoprotein, alanine transaminase, aspartate aminotransferase, free fatty acid, and reactive oxygen species were significantly increased in rats fed a high-fat diet (M) for 8 wk, whereas high-density lipoprotein cholesterol and superoxide dismutase were significantly decreased. However, the body weight and the serum levels of total cholesterol, total glyceride, alanine transaminase, aspartate aminotransferase, free fatty acid, reactive oxygen species, interleukin-8, tumor necrosis factor-α, and interleukin-6 were significantly decreased with fermented milk (T) for 8 wk, and the number of fat vacuoles in hepatocytes was lower than that in the M group. There were significant differences in 19 metabolites in serum between the M group and the C group (administration of nonfermented milk) and in 17 metabolites between the T group and the M group. The contents of 7 different metabolites, glycine, glycerophosphocholine, 1,2-dioleoyl-sn-glycero-3-phosphocholine, thioetheramide-PC, d-aspartic acid, oleic acid, and l-glutamate, were significantly increased in the M group rat serum, and l-palmitoyl carnitine, N6-methyl-l-lysine, thymine, and 2-oxadipic acid were significantly decreased. In the T group rat serum, the contents of 8 different metabolites-1-O-(cis-9-octadecenyl)-2-O-acetyl-sn-glycero-3-phosphocholine, acetylcarnitine, glycine, glycerophosphocholine, 1,2-dioleoyl-sn-glycero-3-phosphocholine, d-aspartic acid, oleic acid, and l-glutamate were significantly decreased, whereas creatinine and thymine were significantly increased. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that 50 metabolic pathways were enriched in the M/C group and T/M group rat serum, of which 12 metabolic pathways were significantly different, mainly distributed in lipid metabolism, amino acid, and endocrine system metabolic pathways. Fermented milk ameliorated inflammation, oxygenation, and hepatocyte injury by regulating lipid metabolism, amino acid metabolic pathways, and related metabolites in the serum of rats with nonalcoholic fatty liver disease.

Low-Dose Administration of Cannabigerol Attenuates Inflammation and Fibrosis Associated with Methionine/Choline Deficient Diet-Induced NASH Model via Modulation of Cannabinoid Receptor

Non-Alcoholic Steatohepatitis (NASH) is the progressive form of Non-Alcoholic Fatty Liver Disease (NAFLD). NASH is distinguished by severe hepatic fibrosis and inflammation. The plant-derived, non-psychotropic compound cannabigerol (CBG) has potential anti-inflammatory effects similar to other cannabinoids. However, the impact of CBG on NASH pathology is still unknown. This study demonstrated the therapeutic potential of CBG in reducing hepatic steatosis, fibrosis, and inflammation.

METHODS

8-week-old C57BL/6 male mice were fed with methionine/choline deficient (MCD) diet or control (CTR) diets for five weeks. At the beginning of week 4, mice were divided into three sub-groups and injected with either a vehicle, a low or high dose of CBG for two weeks. Overall health of the mice, Hepatic steatosis, fibrosis, and inflammation were evaluated.

RESULTS

Increased liver-to-body weight ratio was observed in mice fed with MCD diet, while a low dose of CBG treatment rescued the liver-to-body weight ratio. Hepatic ballooning and leukocyte infiltration were decreased in MCD mice with a low dose of CBG treatment, whereas the CBG treatment did not change the hepatic steatosis. The high dose CBG administration increased inflammation and fibrosis. Similarly, the expression of cannabinoid receptor (CB)1 and CB2 showed decreased expression with the low CBG dose but not with the high CBG dose intervention in the MCD group and were co-localized with mast cells. Additionally, the decreased mast cells were accompanied by decreased expression of transforming growth factor (TGF)-β1.

CONCLUSIONS

Collectively, the low dose of CBG alleviated hepatic fibrosis and inflammation in MCD-induced NASH, however, the high dose of CBG treatment showed enhanced liver damage when compared to MCD only group. These results will provide pre-clinical data to guide future intervention studies in humans addressing the potential uses of CBG for inflammatory liver pathologies, as well as open the door for further investigation into systemic inflammatory pathologies.

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

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

Glucagon-like peptide 1 and fibroblast growth factor-21 in non-alcoholic steatohepatitis: An experimental to clinical perspective

Non-alcoholic steatohepatitis (NASH) is a progressive form of Non-alcoholic fatty liver disease (NAFLD), which slowly progresses toward cirrhosis and finally leads to the development of hepatocellular carcinoma. Obesity, insulin resistance, type 2 diabetes mellitus and the metabolic syndrome are major risk factors contributing to NAFLD. Targeting these risk factors is a rational option for inhibiting NASH progression. In addition, NASH could be treated with therapies that target the metabolic abnormalities causing disease pathogenesis (such as de novo lipogenesis and insulin resistance) as well with medications targeting downstream processes such as cellular damage, apoptosis, inflammation, and fibrosis. Glucagon-like peptide (GLP-1), is an incretin hormone dysregulated in both experimental and clinical NASH, which triggers many signaling pathways including fibroblast growth factor (FGF) that augments NASH pathogenesis. Growing evidence indicates that GLP-1 in concert with FGF-21 plays crucial roles in the conservation of glucose and lipid homeostasis in metabolic disorders. In line, GLP-1 stimulation improves hepatic ballooning, steatosis, and fibrosis in NASH. A recent clinical trial on NASH patients showed that the upregulation of FGF-21 decreases liver fibrosis and hepatic steatosis, thus improving the pathogenesis of NASH. Hence, therapeutic targeting of the GLP-1/FGF axis could be therapeutically beneficial for the remission of NASH. This review outlines the significance of the GLP-1/FGF-21 axis in experimental and clinical NASH and highlights the activity of modulators targeting this axis as potential salutary agents for the treatment of NASH.

The SNP rs516946 Interacted in the Association of MetS with Dietary Iron among Chinese Males but Not Females

This study aimed to explore the role of the single nucleotide polymorphism (SNP) rs516946 of the Ankyrin 1 (ANK1) gene in the relationship between dietary iron and metabolic syndrome (MetS) in the Chinese population. A total of 2766 Chinese adults (1284 males and 1482 females) were recruited. A 3-day 24-h dietary recall and weighing of household condiments were used to assess dietary intake. Anthropometric and laboratory measurements were obtained. After adjusting for age, region, years of education, intentional physical exercise, physical activity level, smoking, alcohol use and energy intake, dietary iron and the SNP rs516946 were both correlated with MetS risk and interacted among the male participants. The trend between dietary iron and MetS risk remained among T allele non-carriers of males but not among T allele carriers of males. Both the SNP rs516946 and the ferritin level correlated positively with the aspartate aminotransferase (AST) level. ANK1 SNP rs516946 interacted in the association of MetS with dietary iron among Chinese males while no association was found among females. Periodic blood loss might prevent females from these associations. The SNP rs516946 might correlate with liver function.

Nonalcoholic fatty liver disease and its prognosis associates with shorter leucocyte telomeres in a 21-year follow-up study

Leucocyte telomere length (LTL) has been associated with nonalcoholic fatty liver disease (NAFLD), but the evidence is imperfect. Furthermore, liver fibrosis has been shown to correlate with mortality and recent studies have also found associations with LTL and fibrosis suggesting that LTL may have additional prognostic value in liver diseases. Our objective was to study the association of LTL and NAFLD and evaluate the association of LTL in prognosis of NAFLD subjects. Study subjects (n = 847) were middle-aged hypertensive patients. All participants were evaluated for NAFLD and their LTL was measured at baseline. Outcomes were obtained from Finnish Causes-of-Death Register and the Care Register for Health Care in Statistics Finland to the end of 2014. An inverse association with NAFLD prevalence and LTL length was observed (p < .001 for trend). Shortest telomere tertile possessed statistically significantly more NAFLD subjects even with multivariate analysis (shortest vs. middle tertile HR 1.98 p = .006 and shortest vs. longest tertile HR 2.03 p = .007). For the study period, mortality of the study group showed statistically significant relation with telomere length in univariate but not for multivariate analysis. In subgroup analysis, LTL did not associate with prognosis of non-NAFLD subjects. However, LTL was inversely associated with overall mortality in the subjects with NAFLD in both univariate (HR 0.16 p = .007) and multivariate analysis (HR 0.20 p = .045). In middle-aged Caucasian cohort, shorter leucocyte telomeres associated independently with increased prevalence of NAFLD. Shorter LTL was not associated with mortality in non-NAFLD patients whereas it predicted mortality of NAFLD patients independently.

Deletion of RNF186 expression suppresses diet-induced hepatic steatosis by regulating insulin activity

RING finger protein186 (RNF186) is dramatically upregulated in steatotic livers. The physiological role of RNF186 in non-alcoholic fatty liver disease (NAFLD) remains obscure. Here, we found that hepatocyte-specific RNF186 knockout (RNF186^LKO) mice were protected from HFD-induced obesity. RNF186 ablation in liver suppressed inflammatory responses and ER stress and alleviated insulin tolerance, leading to improved glucose and lipid metabolism under HFD conditions. RNA-seq and western blot analyses revealed a significant downregulation of peroxisome proliferator-activated receptor γ, stearoyl-CoA desaturase 1, and cluster of differentiation 36 in the liver of RNF186 knockout mice consuming HFD. RNF186 deletion in liver results in less weight gain during HFD feeding and is associated with reduced liver fat, inflammation, and improved glucose and insulin tolerance. In contrast, upregulation of RNF186 in C57BL/6J mice livers impaired lipid metabolism and insulin tolerance. The collective results suggest that RNF186 may be a potential regulator of NAFLD in obesity.

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RNF186 deficiency on high-fat diet alleviates liver steatosis and insulin tolerance

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RNF186 increased hepatic TG accumulation and impaired insulin sensitivity

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RNF186 ablation suppresses hepatic inflammation associated with high-fat diet

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RNF186 maybe a potential regulator of NAFLD in obesity

Obesity and Gallstones

BACKGROUND

The prevalence of obesity has been increasing globally and represents the main risk factor for the development of gallstone disease (GD).

SUMMARY

Excess body weight represents the main cause for the development of GD; nevertheless, there have been described multiple risk factors for its development, among them modifiable risk factors as diet, lifestyle, physical inactivity, and non-modifiable risk factors as ethnicity, female sex, advanced age, parity, and genetic mutations. Body mass index, abdominal perimeter, and waist-hip index have been used to determine the degree of adiposity of a person. Hence, central abdominal fat has been mostly associated with insulin resistance with the consequent increase in the hepatic cholesterol secretion; contributing as one of the multiple mechanisms associated with the development of gallstones. This disease has a low mortality; however, it has been associated with multiple diseases such as cardiovascular diseases, carotid atherosclerosis, metabolic associated fatty liver disease, and gallbladder cancer, probably because they share many of the risk factors.

KEY MESSAGES

GD continues to be considered a disease with a high medical burden, in which it is sought to intervene in modifiable risk factors to reduce its development.

Epigenetics in NAFLD/NASH: Targets and therapy

Recently non-alcoholic fatty liver disease (NAFLD) has grabbed considerable scientific attention, owing to its rapid increase in prevalence worldwide and growing burden on end-stage liver diseases. Metabolic syndrome including obesity, diabetes, and hypertension poses a grave risk to NAFLD etiology and progression. With no drugs available, the mainstay of NAFLD management remains lifestyle changes with exercise and dietary modifications. Nonselective drugs such as metformin, thiazolidinediones (TZDs), ursodeoxycholic acid (UDCA), silymarin, etc., are also being used to target the interrelated pathways for treating NAFLD. Considering the enormous disease burden and the unmet need for drugs, fresh insights into pathogenesis and drug discovery are required. The emergence of the field of epigenetics offers a convincing explanation for the basis of lifestyle, environmental, and other risk factors to influence NAFLD pathogenesis. Therefore, understanding these epigenetic modifications to target the primary cause of the disease might prove a rational strategy to prevent the disease and develop novel therapeutic interventions. Apart from describing the role of epigenetics in the pathogenesis of NAFLD as in other reviews, this review additionally provides an elaborate discussion on exploiting the high plasticity of epigenetic modifications in response to environmental cues, for developing novel therapeutics for NAFLD. Besides, this extensive review provides evidence for epigenetic mechanisms utilized by several potential drugs for NAFLD.

Fasting and overfeeding affect the expression of the immunity- or inflammation-related genes in the liver of poultry via endogenous retrovirus

It is known that nutrition and immunity are connected, but the mechanism is not very clear. Endogenous retroviruses (ERV) account for 8 to 10% of the human and mouse genomes and play an important role in some biological processes of animals. Recent studies indicate that the activation of ERV can affect the expression of the immunity- or inflammation-related genes, and the activities of ERV are subjected to regulation of many factors including nutritional factors. Therefore, we hypothesize that nutritional status can affect the expression of the immunity- or inflammation-related genes via ERV. To verify this hypothesis, the nutritional status of animals was altered by fasting or overfeeding, and the expression of intact ERV (ERVK18P, ERVK25P) and immunity- or inflammation-related genes (DDX41, IFIH1, IFNG, IRF7, STAT3) in the liver was determined by quantitative PCR, followed by overexpressing ERVK25P in goose primary hepatocytes and determining the expression of the immunity- or inflammation-related genes. The data showed that compared with the control group (no fasting), the expression of ERV and the immunity- or inflammation-related genes was increased in the liver of the fasted chickens but decreased in the liver of the fasted geese. Moreover, compared with the control group (routinely fed), the expression of ERV and the immunity- or inflammation-related genes was increased in the liver of the overfed geese. In addition, overexpression of ERVK25P in goose primary hepatocytes can induce the expression of the immunity- or inflammation-related genes. In conclusion, these findings suggest that ERV mediate the effects of fasting and overfeeding on the expression of the immunity- or inflammation-related genes, the mediation varied with poultry species, and ERV and the immunity- or inflammation-related genes may be involved in the development of goose fatty liver. This study provides a potential mechanism for the connection between nutrition and immunity.

Association Between the Triglyceride-Glucose Index and Outcomes of Nonalcoholic Fatty Liver Disease: A Large-Scale Health Management Cohort Study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is increasingly becoming a major health burden. Due to the difficulty of liver biopsy, there is no reliable indicator to evaluate the outcomes of NAFLD. The triglyceride-glucose (TyG) index is a simple and convenient marker of insulin resistance for use in medical practice. Whether the TyG index is predictive of later risk of NAFLD remains unknown.

OBJECTIVE

To evaluate the relationship between TyG index with NAFLD progression and improvement during a median follow-up period of 21 months.

MATERIAL AND METHODS

A total of 11,424 subjects (9327 men) diagnosed with NAFLD were included. The TyG index was calculated as follows: ln [fasting triglycerides (mg/dL) * fasting glucose (mg/dL)/2]. Multivariable Cox regression analysis was applied to analyze the data.

RESULTS

In this study, the severity of NAFLD remained the same in 38.8% of subjects, worsened in 17.4% of subjects, and improved in 43.8% of subjects. Compared with the lowest quartile of the TyG index, the adjusted HR of NAFLD progression in the highest quartile (TyG≥9.34) was 1.448 (1.229 to 1.706), and the adjusted HR of NAFLD improvement was 0.817 (0.723 to 0.923). Subgroup analysis found that smoking increased the correlation between the TyG index and the risk of NAFLD progression, while female, vegan diet, and weight control enhanced the correlation between the TyG index and the risk of NAFLD improvement.

CONCLUSION

The TyG index may be a simple and helpful indicator for further risk appraisal of NAFLD in daily clinical practice.

Association between APOC3 polymorphisms and non-alcoholic fatty liver disease risk: a meta-analysis

BACKGROUND AND AIM

The apolipoprotein C3 (APOC3) polymorphism has been reported to predispose to non-alcoholic fatty liver disease (NAFLD). However, the results remain inconclusive. This meta-analysis aimed to provide insights into the association between APOC3 polymorphisms and NAFLD risk.

METHODS

Studies with terms "NALFD" and "APOC3" were retrieved from PubMed, Web of Science, CNKI and Wanfang databases up to August 1, 2019. Pooled odds ratio (OR) and 95% confidence interval (95% CI) for the association of APOC3 polymorphisms and NAFLD risk were calculated using fixed and random-effects models.

RESULTS

A total of twelve studies from eleven articles were included. Of them, eight studies (1750 cases and 2181 controls) reported the strong association of variant rs2854116 with NAFLD and six studies (1523 cases and 1568 controls) found the association of rs2854117 polymorphism with NAFLD. Overall, a statistically significant association between rs2854116 polymorphism of APOC3 gene and NAFLD risk was found only under dominant model. However, association of rs2854117 polymorphism with NAFLD risk was not detected under all four genetic models. In sub-group analysis of NAFLD subjects based on country, no association among them in China was detected. Besides, four studies analyze the association between the two polymorphisms and clinical characteristics in all subjects or NAFLD patients, and we also failed detect any association between the wild carriers and variant carriers.

CONCLUSION

The meta-analyses suggests that the rs2854116 polymorphism but not rs2854117 polymorphism in APOC3 gene might be a risk factor for NAFLD among Asians. That is, individuals with CT+CC genotype have higher risk of developing NAFLD. However, studies with sufficient sample size are needed for the further validation.

The effects of zinc supplementation on metabolic profile and oxidative stress in overweight/obese patients with non-alcoholic fatty liver disease: A randomized, double-blind, placebo-controlled trial

BACKGROUND

Evidence indicates the positive effects of zinc on insulin resistance and oxidative stress in metabolic syndrome or diabetes. Non-alcoholic fatty liver disease (NAFLD) is the main hepatic manifestation of insulin resistance and metabolic syndrome. The present study is the first clinical trial that evaluated the effects of zinc supplementation on metabolic and oxidative stress status in overweight/obese patients with NAFLD undergoing calorie- restriction diet.

METHODS

Fifty six overweight/obese patients with confirmed mild to moderate NAFLD using ultrasonography were randomly allocated to receive 30 mg elemental zinc supplement (n = 29) or placebo (n = 27) along with weight loss diet for 12 weeks. Serum levels of zinc, homeostasis model of assessment-estimated insulin resistance (HOMA-IR), lipid profile, serum superoxide dismutas1 (SOD1) and malondialdhyde (MDA) levels were assessed.

RESULTS

Serum levels of insulin, SOD1, MDA and HOMA-IR were improved in the treatment group (p < 0.05). Within group comparison showed significant reduction in serum FBS, HbA_1C, TC, LDL-c and TG in the treatment group.

CONCLUSION

Zinc supplementation for three months improved insulin resistance and oxidative stress status in overweight/obese NAFLD patients with no beneficial effects on lipid profiles over weight loss diet. Registration ID in IRCT (IRCT NO: 20181005041238N1).

Exploring Therapeutic Targets to Reverse or Prevent the Transition from Metabolically Healthy to Unhealthy Obesity

The prevalence of obesity and obesity-related metabolic comorbidities are rapidly increasing worldwide, placing a huge economic burden on health systems. Excessive nutrient supply combined with reduced physical exercise results in positive energy balance that promotes adipose tissue expansion. However, the metabolic response and pattern of fat accumulation is variable, depending on the individual’s genetic and acquired susceptibility factors. Some develop metabolically healthy obesity (MHO) and are resistant to obesity-associated metabolic diseases for some time, whereas others readily develop metabolically unhealthy obesity (MUO). An unhealthy response to excess fat accumulation could be due to susceptibility intrinsic factors (e.g., increased likelihood of dedifferentiation and/or inflammation), or by pathogenic drivers extrinsic to the adipose tissue (e.g., hyperinsulinemia), or a combination of both. This review outlines the major transcriptional factors and genes associated with adipogenesis and regulation of adipose tissue homeostasis and describes which of these are disrupted in MUO compared to MHO individuals. It also examines the potential role of pathogenic insulin hypersecretion as an extrinsic factor capable of driving the changes in adipose tissue which cause transition from MHO to MUO. On this basis, therapeutic approaches currently available and emerging to prevent and reverse the transition from MHO to MUO transition are reviewed.

Dyslipidemia as a risk factor for liver fibrosis progression in a multicentric population with non-alcoholic steatohepatitis

Background: Nonalcoholic fatty liver disease (NAFLD) is a serious worldwide health problem, with an estimated global prevalence of 24%; it has a notable relationship with other metabolic disorders, like obesity and type 2 diabetes mellitus (T2DM). Nonalcoholic steatohepatitis (NASH) is one of the most important clinical entities of NAFLD, which is associated with an increased risk of progression to liver cirrhosis and hepatocellular carcinoma (HCC). Mexico is one of the countries with the highest prevalence of metabolic diseases; therefore, we sought to investigate the impact that these clinical entities have in the progression to advanced fibrosis in Mexican patients with NASH. Methods: We performed a multicenter retrospective cross-sectional study, from January 2012 to December 2017. A total of 215 patients with biopsy-proven NASH and fibrosis were enrolled. NASH was diagnosed according NAS score and liver fibrosis was staged by the Kleiner scoring system. For comparing the risk of liver fibrosis progression, we divided our sample into two groups. Those patients with stage F0-F2 liver fibrosis were included in the group with non-significant liver fibrosis (n=178) and those individuals with F3-F4 fibrosis were included in the significant fibrosis group (n=37). We carried out a multivariate analysis to find risk factors associated with liver fibrosis progression. Results: From the 215 patients included, 37 had significant liver fibrosis (F3-4). After logistic regression analysis T2DM (p=0.044), systemic arterial hypertension (p=0.014), cholesterol (p=0.041) and triglycerides (p=0.015) were the main predictor of advanced liver fibrosis. Conclusions: In a Mexican population, dyslipidemia was the most important risk factor associated with advanced liver fibrosis and cirrhosis.

Resveratrol Reduces Lipid Accumulation through Upregulating the Expression of MicroRNAs Regulating Fatty Acid Bet Oxidation in Liver Cells: Evidence from In-vivo and In-vitro Studies

MicroRNAs have been shown to regulate lipogenesis in liver. The aim of the present study was to investigate whether the effects of resveratrol (RSV) on lipogenesis are associated with the changes in the expression of two miRNAs (miR-107 and miR-10b) that regulate lipogenic pathways. 30 wild type C57BL/6j male mice were randomly fed three diets: a standard chow diet (ND), a high fat diet (HFD, 60% fat) and the high fat diet supplemented with 0.4% RSV (HFD-RSV) for 16 weeks. HepG2 cells were treated with high glucose (33 mM) and RSV (20 µM) for 24 h. The expression of the genes and miRNAs were measured by real-time PCR. Triglyceride level was increased in the liver of mice and HepG2 cells. In both animal and In-vitro experiments, triglyceride level was significantly decreased in groups treated with RSV. The expression of the miR-107 and miR-10b was significantly upregulated in the liver of HFD mice, whereas HFD-RSV group demonstrated a significant lower expression of both miRNAs compared to HFD group. In addition, RSV treatment significantly upregulated the expression of CPT-1a and PPARα genes in the liver of HFD mice. Moreover, treatment with RSV could reduce the expression of miR-107 and miR-10b and increase the expression of CPT-1a and PPARα in HG-treated HepG2 cells. These evidence, as a whole, suggest that RSV could exert its anti-lipogenic effect partially through alterations in the expression of miR-107 and miR-10b in liver cells.

Identification of key pathways and genes in nonalcoholic fatty liver disease using bioinformatics analysis

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is one of the most common types of liver disease in the world. However, the molecular mechanisms regulating the development of NAFLD have remained unclear.

MATERIAL AND METHODS

In the present study, we analyzed two public datasets (GSE48452 and GSE89632) to identify differentially expressed mRNAs in the progression of NAFLD. Next, we performed bioinformatics analysis to explore key pathways underlying NAFLD development.

RESULTS

Gene Ontology (GO) analysis showed that differentially expressed genes (DEGs) were mainly involved in regulating a series of metabolism-related pathways (including proteolysis and lipid metabolism), cell proliferation and adhesion, the inflammatory response, and the immune response. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that DEGs in NAFLD were mainly enriched in the insulin signaling pathway, peroxisome proliferator-activated receptor (PPAR) signaling pathway, and p53 signaling pathway. We also constructed protein-protein interaction (PPI) networks for these DEGs. Interestingly, we observed that key hub nodes in PPI networks were also associated with the progression of hepatocellular carcinoma (HCC).

CONCLUSIONS

Taken together, our analysis revealed that a series of pathways, such as metabolism and PPAR signaling pathways, were involved in NAFLD development. Moreover, we observed that many DEGs in NAFLD were also dysregulated in HCC. Although further validation is still needed, we believe this study could provide useful information to explore the potential candidate biomarkers for diagnosis, prognosis, and drug targets of NAFLD.

Relationship between shift work and liver enzymes: a cross-sectional study based on the Korea National Health and Examination Survey (2007-2015)

Background

Shift work has well-known adverse effects on health. However, few studies have investigated the relationship between shift work and hepatic disorders. This study aimed to evaluate the association between shift work and abnormal level of liver enzymes.

Methods

The aggregated data from the 2007–2009, 2010–2012, and 2013–2015 cycles of the Korea National Health and Nutrition Examination Survey was used for this study. The χ² test and multiple logistic regression analysis were used to assess relationship between shift work and abnormal level of liver enzymes stratified by gender.

Results

The odds ratio (OR) of abnormal serum level of alanine aminotransferase (abnormal ALT) in female shift workers was higher with 1.31 (95% confidence interval: 1.00–1.71) compared with day workers after adjusting for covariates. After dividing into subgroups of the shift work pattern, the ORs of abnormal liver enzymes for each pattern compared with day work were not significantly higher.

Conclusions

This study provides limited support for the hypothesis that shift work is related to liver enzyme abnormalities, but offers some evidence in favor of the idea that shift work affects female workers more than males on abnormal ALT. Further studies are needed to define the relationship between shift work and abnormal liver enzymes to be carried out as well as the gender difference in the association.

Hepatoprotective Effect of Jianpi Huoxue Formula on Nonalcoholic Fatty Liver Disease Induced by Methionine-Choline-Deficient Diet in Rat

In parallel with the prevalence metabolic syndrome, nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in most countries. It features a constellation of simple steatosis, nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and even hepatocellular carcinoma. There are no approved drugs for effective management of NAFLD and NASH. Jianpi Huoxue formula (JPHX) mainly consists of Atractylodes macrocephal (Baizhu), Salvia miltiorrhiza (Danshen), Rasux Paeonia Alba (Baishao), Rhizoma Alismatis (Zexie), and Fructus Schisandrae Chinensis (Wuweizi), which may have beneficial effects on NAFLD. The aim of the study was to identify the effect of JPHX on NAFLD. A NAFLD model was induced by methionine-choline-deficient food (MCD) in Wistar rats and orally administered with simultaneous JPHX, once a day for 8 weeks. Hepatocellular injury, lipid profile, inflammation, fibrosis, and apoptosis were evaluated. The results showed that JPHX significantly decreased the abnormal serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels compared with the MCD model (P<0.05). Furthermore, JPHX protected MCD diet-fed rats from accumulation of hepatic triglycerides (TG) and total cholesterol (TC). Histological examination demonstrated that JPHX noticeably normalized the NAFLD activity score (NAS). Moreover, JPHX ameliorated liver inflammation by decreasing TNF-α levels and reduced collagen and matrix metalloproteinases in MCD diet-fed rats. In addition, JPHX prevented rats from MCD-induced cellular apoptosis, as suggested by TUNEL staining, and suppressed the activation of caspase 3 and 7 proteins. JPHX also inhibited the phosphorylation of JNK. In conclusion, JPHX exhibited a hepatoprotective effect against NAFLD in an MCD experimental model.

The Pro12Ala polymorphism in the PPAR-γ2 gene is not associated with an increased risk of NAFLD in Iranian patients with type 2 diabetes mellitus

BACKGROUND

The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily. Several studies have demonstrated a significant association between Pro12Ala polymorphism of the PPAR-γ2 gene and metabolic disorders. Therefore, this study aimed to evaluate the association of Pro12Ala polymorphism with increased risk of NAFLD in Iranian patients with type 2 diabetes mellitus.

METHODS

This cross-sectional study was performed on 145 healthy control subjects and 145 NAFLD patients with a history of type 2 diabetes. Pro12Ala polymorphism genotyping was performed using PCR-restriction fragment length polymorphism (RFLP) technique with the Bs1I restriction enzyme.

RESULTS

Our results demonstrated that CC and GG genotypes of Pro12Ala were found in the participants, but there was no statistically significant difference between NAFLD patients and healthy controls (P = 0.64 and χ2 = 0.21).

CONCLUSION

This study suggests that Pro12Ala polymorphism of the PPAR-γ2 gene cannot be considered as a risk factor for NAFLD in the Iranian population.

Relationship between nonalcoholic fatty liver disease and bone mineral density in adolescents with obesity: a meta-analysis

PURPOSE

Many studies have reported the relationship between nonalcoholic fatty liver disease (NAFLD) and bone mineral density (BMD) among adults. However, fewer studies on this topic have been reported in adolescents. We thus conducted a meta-analysis to show the association between NAFLD and BMD in adolescents with obesity.

MATERIALS AND METHODS

Computer retrieval was carried out via PubMed, Embase, Cochrane Library and the Cochrane Central Register of Controlled Trials from inception to September 2018. Six published case-control studies that assessed the relationship between NAFLD and BMD were included.

RESULTS

The six studies included 217 obese adolescents with NAFLD and 236 controls. The meta-analysis indicated that obese children with NAFLD had a lower BMD and Z-score than the control group (weighted mean difference [WMD]-0.03, 95% CI [-0.05, -0.02], P=0.000; [WMD] -0.26, 95% CI [-0.37, -0.14], P=0.000). However, we analyzed the factor of bone mineral content, and there was no correlation between the two groups ([WMD]-55.99, 95% CI [-132.16, 20.18], P=0.150).

CONCLUSION

Obese children with NAFLD are more susceptible to osteoporosis than children with only obesity. Because of the limitations related to the quantity and quality of the included literature, further studies are still needed.

MicroRNAs as a Novel Tool in the Diagnosis of Liver Lipid Dysregulation and Fatty Liver Disease

In recent years, metabolic disorder, especially fatty liver disease, has been considered a major challenge to global health. The attention of researchers focused on expanding knowledge of the regulation mechanism behind these diseases and towards the new diagnostics tools and treatments. The pathophysiology of the fatty liver disease is undoubtedly complex. Abnormal hepatic lipid accumulation is a major symptom of most metabolic diseases. Therefore, the identification of novel regulation factors of lipid metabolism is important and meaningful. As a new diagnostic tool, the function of microRNAs during fatty liver disease has recently come into notice in biological research. Accumulating evidence supports the influence of miRNAs in lipid metabolism. In this review, we discuss the potential role of miRNAs in liver lipid metabolism and the pathogenesis of fatty liver disease.

Association between Vitamin D Status and Non-Alcoholic Fatty Liver Disease: A Population-Based Study

The relationship between vitamin D levels and non-alcoholic fatty liver disease (NAFLD) remains unestablished. In this study, we aimed to explore the relationship between vitamin D levels and NAFLD based on population survey data. This cross-sectional study was conducted based on data from the National Health and Nutrition Examination Survey. Liver steatosis was diagnosed by ultrasonography. Binary logistic regression analyses were performed to determine the relationship between vitamin D status and NAFLD. A total of 9,782 participants were identified in this analysis, with 46.8% male and an average age of 44.41±0.16 y old. Among them, 6,047 (61.8%) cases were without NAFLD, 1,357 (13.9%) had mild NAFLD, 1,594 (16.3%) had moderate and 784 (8.0%) had severe NAFLD. Compared to those with non-NAFLD or mild NAFLD, patients in the moderate to severe NAFLD group had higher vitamin D deficiency or insufficiency rates (12.4% vs 11.5% and 36.8% vs 33.2%, respectively). After adjustment for male gender, older age, race, BMI, history of diabetes and vitamin D intake, vitamin D levels were independently associated with the severity of NAFLD (vitamin D deficiency group OR: 1.314, 95% CI: 1.129 to 1.529, vitamin D insufficiency group OR: 1.203, 95% CI: 1.090 to 1.328). Besides that, cold season was also found to be an independent factor for NAFLD (OR: 0.896, 95% CI: 0.820 to 0.979). Lower vitamin D level is an independent risk factor for NAFLD. Vitamin D levels are inversely associated with the severity of NAFLD. Cold season increases the risk of NAFLD independently.

Role of vitamin E in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide. NAFLD manifests as hepatic lipid accumulation, insulin resistance, and inflammation, and can progress to nonalcoholic steatohepatitis (NASH) and cirrhosis. However, the underlying mechanisms of NAFLD, including those that drive its progression, are unclear. Both liver-resident (Kupffer cells) and recruited macrophages play a crucial role in the development of insulin resistance and NASH. Therefore, NALFD could potentially be ameliorated by modifying the polarization of macrophages/Kupffer cells. Reactive oxygen species induce oxidative stress, which is implicated in the progression of NASH. Micronutrients, including vitamins, are potent antioxidants that exert anti-inflammatory effects, and are used in the treatment of NAFLD. We review here the molecular mechanisms of the pathogenesis of NAFLD and the potential utility of vitamin E in its prevention and/or treatment. © 2018 IUBMB Life, 71(4):516-522, 2019.

Hepatoprotective Effects of MHY3200 on High-Fat, Diet-Induced, Non-Alcoholic Fatty Liver Disease in Rats

This study investigated the effects of 2-(4-(5-chlorobenzo[d]thiazol-2-yl)phenoxy)-2,2-difluoroacetic acid (MHY3200) on high-fat diet (HFD)-induced hepatic lipid accumulation and inflammation. The measurement of peroxisome proliferator-activated receptor (PPAR)α activity by using a luciferase assay indicated that MHY3200 was more potent than a known PPARα agonist, WY14643, in AC2F cells. Six-month-old male SD rats were fed chow or HFD for 1 month, and after, with or without added MHY3200 (1 or 2 mg/kg/day) for 4 weeks. The oral administration of MHY3200 caused a significant decrease in serum triglyceride (TG), glucose, alanine aminotransferase, and insulin, as well as a slight decrease in the level of free fatty acid and aspartate transaminase. No weight gain was detected when compared with HFD rats, and hepatic TG content was also attenuated by the administration of MHY3200. Furthermore, phosphorylation of the ER stress marker, inositol-requiring kinase 1 and its downstream gene, c-Jun N-terminal kinase, in addition to serine phosphorylation of insulin receptor substrate 1 were suppressed by MHY3200. Consistent with these results, MHY3200 administration reduced the levels of activation of protein-1, cyclooxygenase-2, and inducible nitric oxide synthase. Our results suggested that MHY3200 ameliorated HFD-induced hepatic lipid accumulation and inflammation, and improved insulin resistance through PPARα activation.

Long-term outcomes of patients undergoing simultaneous liver transplantation and sleeve gastrectomy

Obesity is increasingly common before and after liver transplantation (LT), yet optimal management remains unclear. The aim of this study was to analyze the long-term outcomes for obese patients undergoing LT, including a noninvasive weight loss program and combined LT and sleeve gastrectomy (SG). Since 2006, all patients referred for LT with a body mass index (BMI) ≥35 kg/m² were enrolled. Patients who achieved weight loss (BMI <35) underwent LT alone, and those who did not underwent simultaneous LT + SG. Analysis of long-term outcomes for patients ≥3 years posttransplant was performed. Since 2006, there were 36 in the weight loss intervention (LT cohort) and 13 in the LT + SG cohort with >3 years of follow-up, whereas overall, a total of 29 patients underwent LT + SG. Patients in the LT cohort had less severe obesity at enrollment (40.0 ± 2.7 vs. LT + SG cohort 46.0 ± 4.5; P < 0.001). In the LT cohort, 83.3% (30 of 36) achieved >10% loss in total body weight (TBW) pre-LT. Three years posttransplant, 29.4% of patients in the LT cohort maintained >10% loss in TBW, whereas 100% of the LT + SG patients did (P < 0.001). Patients who underwent LT + SG maintained a significantly higher percentage of total body weight loss after 3 years of follow-up (LT cohort 3.9 ± 13.3% vs. LT + S G cohort 34.8 ± 17.3%; P < 0.001). Patients in the LT + SG also had a lower prevalence of hypertension, insulin resistance, and hepatic steatosis and required fewer antihypertensive medications and lipid agents at last follow-up.

CONCLUSION

Whereas weight loss before transplantation was achieved by obese patients, weight regain was common in the LT cohort. Combined LT + SG resulted in more effective and more durable weight loss, as well as fewer metabolic complications at last follow-up. (Hepatology 2018).

Insulin/Snail1 axis ameliorates fatty liver disease by epigenetically suppressing lipogenesis

Insulin stimulates lipogenesis but insulin resistance is also associated with increased hepatic lipogenesis in obesity. However, the underlying mechanism remains poorly characterized. Here, we show a noncanonical insulin-Snail1 pathway that suppresses lipogenesis. Insulin robustly upregulates zinc-finger protein Snail1 in a PI 3-kinase-dependent manner. In obesity, the hepatic insulin-Snail1 cascade is impaired due to insulin resistance. Hepatocyte-specific deletion of Snail1 enhances insulin-stimulated lipogenesis in hepatocytes, exacerbates dietary NAFLD in mice, and attenuates NAFLD-associated insulin resistance. Liver-specific overexpression of Snail1 has the opposite effect. Mechanistically, Snail1 binds to the fatty acid synthase promoter and recruits HDAC1/2 to induce deacetylation of H3K9 and H3K27, thereby repressing fatty acid synthase promoter activity. Our data suggest that insulin pathways bifurcate into canonical (lipogenic) and noncanonical (anti-lipogenesis by Snail1) two arms. The noncanonical arm counterbalances the canonical arm through Snail1-elicited epigenetic suppression of lipogenic genes. Impairment in the insulin-Snail1 arm may contribute to NAFLD in obesity.

Novel PPARα agonist MHY553 alleviates hepatic steatosis by increasing fatty acid oxidation and decreasing inflammation during aging

Hepatic steatosis is frequently observed in obese and aged individuals. Because hepatic steatosis is closely associated with metabolic syndromes, including insulin resistance, dyslipidemia, and inflammation, numerous efforts have been made to develop compounds that ameliorate it. Here, a novel peroxisome proliferator-activated receptor (PPAR) α agonist, 4-(benzo[d]thiazol-2-yl)benzene-1,3-diol (MHY553) was developed, and investigated its beneficial effects on hepatic steatosis using young and old Sprague-Dawley rats and HepG2 cells.

Docking simulation and Western blotting confirmed that the activity of PPARα, but not that of the other PPAR subtypes, was increased by MHY553 treatment. When administered orally, MHY553 markedly ameliorated aging-induced hepatic steatosis without changes in body weight and serum levels of liver injury markers. Consistent with in vivo results, MHY553 inhibited triglyceride accumulation induced by a liver X receptor agonist in HepG2 cells. Regarding underlying mechanisms, MHY553 stimulated PPARα translocation into the nucleus and increased mRNA levels of its downstream genes related to fatty acid oxidation, including CPT-1A and ACOX1, without apparent change in lipogenesis signaling. Furthermore, MHY553 significantly suppresses inflammatory mRNA expression in old rats. In conclusion, MHY553 is a novel PPARα agonist that improved aged-induced hepatic steatosis, in part by increasing β-oxidation signaling and decreasing inflammation in the liver. MHY553 is a potential pharmaceutical agent for treating hepatic steatosis in aging.

Nonalcoholic fatty liver disease remission in men through regular exercise

Recent cross-sectional and randomized controlled studies of small sample sizes revealed that regular exercise is effective for improving nonalcoholic fatty liver disease. However, there has been no large-scale longitudinal study addressing the effect of regular exercise on remission of nonalcoholic fatty liver disease. Thus, we investigated the impact of exercise on the natural history of nonalcoholic fatty liver disease. We analyzed 1,010 (860 men and 150 women) Japanese participants who received health checkups repeatedly over 10 years by a historical cohort study and were diagnosed with nonalcoholic fatty liver disease at baseline. Regular exercise was defined as participating in any kind of sports at least once a week. Nonalcoholic fatty liver disease was diagnosed by ultrasonographic images. During 10 years of follow-up, remission of nonalcoholic fatty liver disease was observed in 46.0% (396/860) of men and 48.7% (73/150) of women. In men, the adjusted hazard ratio of regular exercise for remission of nonalcoholic fatty liver disease was 1.46 (95% confidence interval 1.10–1.95, p = 0.010). However, this was not significant in women. Exercise at least once a week is implicated in the remission of nonalcoholic fatty liver disease in men.

More Evidence for the Genetic Susceptibility of Mexican Population to Nonalcoholic Fatty Liver Disease through PNPLA3

BACKGROUND

The gene for patatin-like phospholipase domain containing 3 (PNPLA3) is associated with nonalcoholic fatty liver disease (NAFLD) development. We previously found that Mexican indigenous population had the highest frequency reported of the PNPLA3 148M risk allele. Further, we observed a relationship between M148M genotype with elevated ALT levels in individuals with normal weight, overweight and obese. We sought to investigate whether PNPLA3 polymorphism is associated with NAFLD development in Mexicans.

MATERIAL AND METHODS

We enrolled 189 Mexican patients with NAFLD and 201 healthy controls. Anthropometric, metabolic, and biochemical variables were measured, and rs738409 (Ile148Met substitution) polymorphism was genotyped by sequencing.

RESULTS

Logistic regression analysis, using a recessive model, suggested that PNPLA3 polymorphism in Mexican population is significantly associated (OR = 1.711, 95% CI: 1.014-2.886; P = 0.044) with NAFLD.

CONCLUSIONS

The PNPLA3 gene is associated with NAFLD in Mexican population. More studies are required to explain the high prevalence of PNPLA3 polymorphism in Mexican-Americans, Mexican-Indians, and Mexican-Mestizos.

Chinese olive extract ameliorates hepatic lipid accumulation in vitro and in vivo by regulating lipid metabolism

Chinese olive contains plenty of polyphenols, which possess a wide range of biological actions. In this study, we aimed to investigate the role of the ethyl acetate fraction of Chinese olive fruit extract (CO-EtOAc) in the modulation of lipid accumulation in vitro and in vivo. In cellular studies, CO-EtOAc attenuated oleic acid-induced lipid accumulation; we then elucidated the molecular mechanisms of CO-EtOAc in FL83B mouse hepatocytes. CO-EtOAc suppressed the mRNA levels of fatty acid transporter genes (CD36 and FABP) and lipogenesis genes (SREBP-1c, FAS, and ACC1), but upregulated genes that govern lipolysis (HSL) and lipid oxidation (PPARα, CPT-1, and ACOX). Moreover, CO-EtOAc increased the protein expression of phosphorylated AMPK, ACC1, CPT-1, and PPARα, but downregulated the expression of mature SREBP-1c and FAS. AMPK plays an essential role in CO-EtOAc-mediated amelioration of lipid accumulation. Furthermore, we confirmed that CO-EtOAc significantly inhibited body weight gain, epididymal adipose tissue weight, and hepatic lipid accumulation via regulation of the expression of fatty acid transporter, lipogenesis, and fatty acid oxidation genes and proteins in C57BL/6 mice fed a 60% high-fat diet. Therefore, Chinese olive fruits may have the potential to improve the metabolic abnormalities associated with fatty liver under high fat challenge.

Association of serum ferritin with non-alcoholic fatty liver disease: a meta-analysis

Background

A growing number of studies reported the connection between the level of serum ferritin (SFL) and non-alcoholic fatty liver disease (NAFLD). However, such connection was still disputable. The aim of our meta-analysis was to estimate SFL between the groups as below: patients with NAFLD against control group; non-alcoholic steatohepatitis (NASH) patients against control group; non-alcoholic fatty liver (NAFL) patients against a control group and NASH patients vs NAFL patients.

Methods

We screened the studies in PubMed, EMBASE, the Cochrane Database and the Cochrane Central register controlled trials from the beginning to July 10, 2016 to find the studies indicated the connection between SFL and NAFLD (NAFL and/or NASH). Fourteen published studies which evaluate the SFL in NAFLD patients were selected.

Results

Higher SFL was noticed in NAFLD patients against control group (standardized mean difference [SMD] 1.01; 95% CI 0.89, 1.13), NASH patients against control group (SMD 1.21; 95% CI 1.00, 1.42), NAFL patients against control group (SMD 0.51; 95% CI 0.24, 0.79) and NASH patients against NAFL patients (SMD 0.63; 95% CI 0.52, 0.75). These results remained unaltered actually after the elimination of studies which were focused on paediatric or adolescent populations. Higher SFL was presented in NAFLD patients against the control group (SMD 1.08; 95% CI 0.95, 1.20) in adults and NASH patients against NAFL patients in adults (SMD 0.74; 95% CI 0.62, 0.87). The connection between SFL and NASH against NAFL group in paediatric or adolescent populations was observed inconsistently (SMD 0.10; 95% CI -0.18, 0.38).

Conclusions

The level of SFL was elevated in patients with NAFLD (NAFL and/or NASH) compared with the controls. Compared with NAFL, The level of SFL was increased in NASH. The result remained unaltered actually after the elimination of studies focused on paediatric or adolescent populations.

Root bark of Ulmus davidiana var. japonica restrains acute alcohol-induced hepatic steatosis onset in mice by inhibiting ROS accumulation

Alcohol-induced hepatic steatosis and inflammation are key drivers of alcohol-induced liver injury, mainly caused by oxidative stress. The roots bark of Ulmus davidiana var. japonica is well known for its substantial antioxidative and antitumorigenic potency. In this study, we examined whether this plant can ameliorate alcohol-induced liver injuries characterized by hepatic steatosis and inflammation through its antioxidative activity. C57BL/6J mice were treated with the root bark extract of Ulmus davidiana var. japonica (RUE; 100 mg of extract/kg bodyweight; oral gavage) and alcohol (1 g/kg of bodyweight; oral gavage) for 5 days. Markers of acute alcohol-induced hepatic steatosis were determined and putative molecular mechanisms responsible for the protection of RUE were investigated. RUE noticeably protected against alcohol-induced hepatic steatosis and inflammation. Reactive oxygen species (ROS), over-produced by alcohol, negatively orchestrated various signaling pathways involved in the lipid metabolism and inflammation. These pathways were restored through the ROS scavenging activity of RUE in the liver. In particular, the expression of lipogenic genes (e.g., SREBP-1, ACC, and FAS) and inflammatory cytokines (e.g., IL-1β, and NF-κB p65) significantly decreased with RUE treatment. Conversely, the expression of fatty acid oxidation-related genes (e.g., SIRT1, AMPKα, and PGC1α) were increased in mice treated with RUE. Thus, the results indicate that RUE counteracts and thus attenuates alcoholic hepatic steatosis onset in mice, possibly by suppressing ROS-mediated steatosis and inflammation.

Astragaloside IV attenuates free fatty acid-induced ER stress and lipid accumulation in hepatocytes via AMPK activation

Although the pathogenesis of non-alcoholic fatty liver disease (NAFLD) is not completely understood, the increased influx of free fatty acids (FFAs) into the liver and the FFA-induced hepatic endoplasmic reticulum (ER) stress are two crucial pathogenic processes in the initiation and development of NAFLD. In this study we investigated the effects of astragaloside IV (AS-IV), a bioactive compound purified from Astragali Radix, on FFA-induced lipid accumulation in hepatocytes and elucidated the underlying mechanisms. Human HepG2 cells and primary murine hepatocytes were exposed to FFAs (1 mmol/L, oleate/palmitate, 2:1 ratio) with or without AS-IV for 24 h. Exposure to FFAs induced marked lipid accumulation in hepatocytes, whereas co-treatment with AS-IV (100 μg/mL) significantly attenuated this phenomenon. Notably, AS-IV (50-200 μg/mL) concentration-dependently enhanced the phosphorylation of AMPK, acetyl-CoA carboxylase (ACC) and SREBP-1c, inhibited the accumulation and nuclear translocation of mature SREBP-1 and subsequently decreased the mRNA levels of lipogenic genes including acc1, fas and scd1. AS-IV treatment also concentration-dependently attenuated FFA-induced hepatic ER stress evidenced by the reduction of the key markers, GRP78, CHOP and p-PERK. Pretreated the cells with the AMPK inhibitor compound C (20 μmol/L) greatly diminished these beneficial effects of AS-IV. Our results demonstrate that AS-IV attenuates FFA-induced ER stress and lipid accumulation in an AMPK-dependent manner in hepatocytes, which supports its use as promising therapeutics for hepatic steatosis.

Nonalcoholic Fatty Liver Disease and Insulin Resistance: New Insights and Potential New Treatments

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver disorders worldwide. It is associated with clinical states such as obesity, insulin resistance, and type 2 diabetes, and covers a wide range of liver changes, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH), liver cirrhosis, and hepatocellular carcinoma. Metabolic disorders, such as lipid accumulation, insulin resistance, and inflammation, have been implicated in the pathogenesis of NAFLD, but the underlying mechanisms, including those that drive disease progression, are not fully understood. Both innate and recruited immune cells mediate the development of insulin resistance and NASH. Therefore, modifying the polarization of resident and recruited macrophage/Kupffer cells is expected to lead to new therapeutic strategies in NAFLD. Oxidative stress is also pivotal for the progression of NASH, which has generated interest in carotenoids as potent micronutrient antioxidants in the treatment of NAFLD. In addition to their antioxidative function, carotenoids regulate macrophage/Kupffer cell polarization and thereby prevent NASH progression. In this review, we summarize the molecular mechanisms involved in the pathogenesis of NAFLD, including macrophage/Kupffer cell polarization, and disturbed hepatic function in NAFLD. We also discuss dietary antioxidants, such as β-cryptoxanthin and astaxanthin, that may be effective in the prevention or treatment of NAFLD.