Nonalcoholic fatty liver disease

Metabolic Dysfunction-Associated Steatotic Liver Disease: From Pathogenesis to Current Therapeutic Options

The epidemiological burden of liver steatosis associated with metabolic diseases is continuously growing worldwide and in all age classes. This condition generates possible progression of liver damage (i.e., inflammation, fibrosis, cirrhosis, hepatocellular carcinoma) but also independently increases the risk of cardio-metabolic diseases and cancer. In recent years, the terminological evolution from "nonalcoholic fatty liver disease" (NAFLD) to "metabolic dysfunction-associated fatty liver disease" (MAFLD) and, finally, "metabolic dysfunction-associated steatotic liver disease" (MASLD) has been paralleled by increased knowledge of mechanisms linking local (i.e., hepatic) and systemic pathogenic pathways. As a consequence, the need for an appropriate classification of individual phenotypes has been oriented to the investigation of innovative therapeutic tools. Besides the well-known role for lifestyle change, a number of pharmacological approaches have been explored, ranging from antidiabetic drugs to agonists acting on the gut-liver axis and at a systemic level (mainly farnesoid X receptor (FXR) agonists, PPAR agonists, thyroid hormone receptor agonists), anti-fibrotic and anti-inflammatory agents. The intrinsically complex pathophysiological history of MASLD makes the selection of a single effective treatment a major challenge, so far. In this evolving scenario, the cooperation between different stakeholders (including subjects at risk, health professionals, and pharmaceutical industries) could significantly improve the management of disease and the implementation of primary and secondary prevention measures. The high healthcare burden associated with MASLD makes the search for new, effective, and safe drugs a major pressing need, together with an accurate characterization of individual phenotypes. Recent and promising advances indicate that we may soon enter the era of precise and personalized therapy for MASLD/MASH.

Supplementation of Micro- and Macronutrients-A Role of Nutritional Status in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a condition in which the pathological cumulation of fat with coexisting inflammation and damage of hepatic cells leads to progressive dysfunctions of the liver. Except for the commonly well-known major causes of NAFLD such as obesity, dyslipidemia, insulin resistance, or diabetes, an unbalanced diet and imbalanced nutritional status should also be taken into consideration. In this narrative review, we summarized the current knowledge regarding the micro- and macronutrient status of patients suffering from NAFLD considering various diets and supplementation of chosen supplements. We aimed to summarize the knowledge indicating which nutritional impairments may be associated with the onset and progression of NAFLD at the same time evaluating the potential therapy targets that could facilitate the healing process. Except for the above-mentioned objectives, one of the most important aspects of this review was to highlight the possible strategies for taking care of NAFLD patients taking into account the challenges and opportunities associated with the micronutrient status of the patients. The current research indicates that a supplementation of chosen vitamins (e.g., vitamin A, B complex, C, or D) as well as chosen elements such as zinc may alleviate the symptoms of NAFLD. However, there is still a lack of sufficient data regarding healthy ranges of dosages; thus, further research is of high importance in this matter.

Thyroid hormone action and liver disease, a complex interplay

Thyroid hormone action is involved in virtually all physiological processes. It is well known that the liver and thyroid are intimately linked, with thyroid hormone playing important roles in de novo lipogenesis, beta-oxidation (fatty acid oxidation), cholesterol metabolism, and carbohydrate metabolism. Clinical and mechanistic research studies have shown that thyroid hormone can be involved in chronic liver diseases, including alcohol-associated or NAFLD and HCC. Thyroid hormone action and synthetic thyroid hormone analogs can exert beneficial actions in terms of lowering lipids, preventing chronic liver disease and as liver anticancer agents. More recently, preclinical and clinical studies have indicated that some analogs of thyroid hormone could also play a role in the treatment of liver disease. These synthetic molecules, thyromimetics, can modulate lipid metabolism, particularly in NAFLD/NASH. In this review, we first summarize the thyroid hormone signaling axis in the context of liver biology, then we describe the changes in thyroid hormone signaling in liver disease and how liver diseases affect the thyroid hormone homeostasis, and finally we discuss the use of thyroid hormone-analog for the treatment of liver disease.

Suppression of NASH-Related HCC by Farnesyltransferase Inhibitor through Inhibition of Inflammation and Hypoxia-Inducible Factor-1α Expression

Inflammatory processes play major roles in carcinogenesis and the progression of hepatocellular carcinoma (HCC) derived from non-alcoholic steatohepatitis (NASH). But, there are no therapies for NASH-related HCC, especially focusing on these critical steps. Previous studies have reported that farnesyltransferase inhibitors (FTIs) have anti-inflammatory and anti-tumor effects. However, the influence of FTIs on NASH-related HCC has not been elucidated. In hepatoblastoma and HCC cell lines, HepG2, Hep3B, and Huh-7, we confirmed the expression of hypoxia-inducible factor (HIF)-1α, an accelerator of tumor aggressiveness and the inflammatory response. We established NASH-related HCC models under inflammation and free fatty acid burden and confirmed that HIF-1α expression was increased under both conditions. Tipifarnib, which is an FTI, strongly suppressed increased HIF-1α, inhibited cell proliferation, and induced apoptosis. Simultaneously, intracellular interleukin-6 as an inflammation marker was increased under both conditions and significantly suppressed by tipifarnib. Additionally, tipifarnib suppressed the expression of phosphorylated nuclear factor-κB and transforming growth factor-β. Finally, in a NASH-related HCC mouse model burdened with diethylnitrosamine and a high-fat diet, tipifarnib significantly reduced tumor nodule formation in association with decreased serum interleukin-6. In conclusion, tipifarnib has anti-tumor and anti-inflammatory effects in a NASH-related HCC model and may be a promising new agent to treat this disease.

NAFLD, MAFLD, and beyond: one or several acronyms for better comprehension and patient care

The term non-alcoholic fatty liver disease (NAFLD) has rapidly become the most common type of chronic liver disease. NAFLD points to excessive hepatic fat storage and no evidence of secondary hepatic fat accumulation in patients with "no or little alcohol consumption". Both the etiology and pathogenesis of NAFLD are largely unknown, and a definitive therapy is lacking. Since NAFLD is very often and closely associated with metabolic dysfunctions, a consensus process is ongoing to shift the acronym NAFLD to MAFLD, i.e., metabolic-associated fatty liver disease. The change in terminology is likely to improve the classification of affected individuals, the disease awareness, the comprehension of the terminology and pathophysiological aspects involved, and the choice of more personalized therapeutic approaches while avoiding the intrinsic stigmatization due to the term "non-alcoholic". Even more recently, other sub-classifications have been proposed to concentrate the heterogeneous causes of fatty liver disease under one umbrella. While awaiting additional validation studies in this field, we discuss the main reasons underlying this important shift of paradigm.

Effect of Hepatic Pathology on Liver Regeneration: The Main Metabolic Mechanisms Causing Impaired Hepatic Regeneration

Liver regeneration has been studied for many decades, and the mechanisms underlying regeneration of normal liver following resection are well described. However, no less relevant is the study of mechanisms that disrupt the process of liver regeneration. First of all, a violation of liver regeneration can occur in the presence of concomitant hepatic pathology, which is a key factor reducing the liver's regenerative potential. Understanding these mechanisms could enable the rational targeting of specific therapies to either reduce the factors inhibiting regeneration or to directly stimulate liver regeneration. This review describes the known mechanisms of normal liver regeneration and factors that reduce its regenerative potential, primarily at the level of hepatocyte metabolism, in the presence of concomitant hepatic pathology. We also briefly discuss promising strategies for stimulating liver regeneration and those concerning methods for assessing the regenerative potential of the liver, especially intraoperatively.

Are Nonalcoholic Fatty Liver Disease and Bone Mineral Density Associated? - A Cross-Sectional Study Using Liver Biopsy and Dual-Energy X-Ray Absorptiometry

There is controversy regarding the association between nonalcoholic fatty liver disease (NAFLD) and osteoporosis. Our study aim was to assess bone mineral density (BMD) in patients with biopsy-proven NAFLD and examine if the severity of NAFLD affects BMD. A total of 147 adult women (n = 108) and men (n = 39) aged 18-76 years (mean ± standard deviation [SD] age 45.3 ± 12.5) were recruited in this cross-sectional study and underwent a liver biopsy and dual-energy X-ray absorptiometry (DXA). NAFLD activity score (NAS) based on the degree of steatosis, lobular inflammation and hepatocellular ballooning was used to assess NAFLD severity. The majority of subjects, 53%, had steatosis, 25% had nonalcoholic steatohepatitis (NASH) whereas 23% served as control subjects with no evidence of NAFLD. There were no significant differences in the lumbar spine (1.09 ± 0.12, 1.11 ± 0.18, and 1.12 ± 0.15 g/cm², p = 0.69, in controls, steatosis, and NASH, respectively) or hip BMD (1.10 ± 0.15, 1.12 ± 0.13, and 1.09 ± 0.13 g/cm², p = 0.48, in controls, steatosis, and NASH, respectively) between the groups. Adjusting for age, gender, body mass index, and diabetes in multiple regression models did not alter the results. There was no correlation between NAS and neither lumbar spine BMD (r = 0.06, p = 0.471), nor hip BMD (r = -0.03, p = 0.716). In conclusion, BMD was similar across the spectrum of NAFLD in both genders and not related to the severity of the underlying histological lesions, suggesting that neither steatosis nor NASH exerts a detrimental effect on BMD in these relatively young patients. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Potential Therapeutic Implication of Herbal Medicine in Mitochondria-Mediated Oxidative Stress-Related Liver Diseases

Mitochondria are double-membrane organelles that play a role in ATP synthesis, calcium homeostasis, oxidation-reduction status, apoptosis, and inflammation. Several human disorders have been linked to mitochondrial dysfunction. It has been found that traditional therapeutic herbs are effective on alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) which are leading causes of liver cirrhosis and hepatocellular carcinoma. The generation of reactive oxygen species (ROS) in response to oxidative stress is caused by mitochondrial dysfunction and is considered critical for treatment. The role of oxidative stress, lipid toxicity, and inflammation in NAFLD are well known. NAFLD is a chronic liver disease that commonly progresses to cirrhosis and chronic liver disease, and people with obesity, insulin resistance, diabetes, hyperlipidemia, and hypertension are at a higher risk of developing NAFLD. NAFLD is associated with a number of pathological factors, including insulin resistance, lipid metabolic dysfunction, oxidative stress, inflammation, apoptosis, and fibrosis. As a result, the improvement in steatosis and inflammation is enough to entice researchers to look into liver disease treatment. However, antioxidant treatment has not been very effective for liver disease. Additionally, it has been suggested that the beneficial effects of herbal medicines on immunity and inflammation are governed by various mechanisms for lipid metabolism and inflammation control. This review provided a summary of research on herbal medicines for the therapeutic implementation of mitochondria-mediated ROS production in liver disease as well as clinical applications through herbal medicine. In addition, the pathophysiology of common liver disorders such as ALD and NAFLD would be investigated in the role that mitochondria play in the process to open new therapeutic avenues in the management of patients with liver disease.

Gut microbiome and microbial metabolites in NAFLD and after bariatric surgery: Correlation and causality

Non-alcoholic fatty liver disease (NAFLD) is currently related to a heavy socioeconomic burden and increased incidence. Since obesity is the most prevalent risk factor for NAFLD, weight loss is an effective therapeutic solution. Bariatric surgery (BS), which can achieve long-term weight loss, improves the overall health of patients with NAFLD. The two most common surgeries are the Roux-en-Y gastric bypass and sleeve gastrectomy. The gut-liver axis is the complex network of cross-talking between the gut, its microbiome, and the liver. The gut microbiome, involved in the homeostasis of the gut-liver axis, is believed to play a significant role in the pathogenesis of NAFLD and the metabolic improvement after BS. Alterations in the gut microbiome in NAFLD have been confirmed compared to that in healthy individuals. The mechanisms linking the gut microbiome to NAFLD have been proposed, including increased intestinal permeability, higher energy intake, and other pathophysiological alterations. Interestingly, several correlation studies suggested that the gut microbial signatures after BS become more similar to those of lean, healthy controls than that of patients with NAFLD. The resolution of NAFLD after BS is related to changes in the gut microbiome and its metabolites. However, confirming a causal link remains challenging. This review summarizes characteristics of the gut microbiome in patients with NAFLD before and after BS and accumulates existing evidence about the underlying mechanisms of the gut microbiome.

Multidisciplinary approach for hepatocellular carcinoma arising from cirrhotic liver with Budd-Chiari syndrome: a case report

Budd-Chiari syndrome (BCS) is defined by the obstruction of the hepatic venous outflow between the small hepatic veins and the junction of the inferior vena cava (IVC) with the right atrium. BCS with IVC obstruction occasionally progresses to hepatocellular carcinoma (HCC). Here, we report the case of a patient with HCC arising from a cirrhotic liver with BCS, in whom the hepatic portion of the IVC was obstructed, and who had a favorable outcome with a multidisciplinary approach and IVC balloon angioplasty.

The role of microbiota in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most frequent liver disease worldwide. Gut microbiota can play a role in the pathogenesis of NAFLD since dysbiosis is associated with reduced bacterial diversity, altered Firmicutes/Bacteroidetes ratio, a relative abundance of alcohol-producing bacteria, or other specific genera. Changes can promote disrupted intestinal barrier and hyperpermeability, filtration of bacterial products, activation of the immune system, and pro-inflammatory changes in the intestine, in the liver, and at a systemic level. Microbiota-derived molecules can contribute to the steatogenic effects. The link between gut dysbiosis and NAFLD, however, is confused by several factors which include age, BMI, comorbidities, dietary components, and lifestyle. The role of toxic chemicals in food and water requires further studies in both gut dysbiosis and NAFLD. We can anticipate that gut microbiota manipulation will represent a potential therapeutic tool to delay or reverse the progression of NAFLD, paving the way to primary prevention measures.

Iron overload in alcoholic liver disease: underlying mechanisms, detrimental effects, and potential therapeutic targets

Alcoholic liver disease (ALD) is a global public health challenge due to the high incidence and lack of effective therapeutics. Evidence from animal studies and ALD patients has demonstrated that iron overload is a hallmark of ALD. Ethanol exposure can promote iron absorption by downregulating the hepcidin expression, which is probably mediated by inducing oxidative stress and promoting erythropoietin (EPO) production. In addition, ethanol may enhance iron uptake in hepatocytes by upregulating the expression of transferrin receptor (TfR). Iron overload in the liver can aggravate ethanol-elicited liver damage by potentiating oxidative stress via Fenton reaction, promoting activation of Kupffer cells (KCs) and hepatic stellate cells (HSCs), and inducing a recently discovered programmed iron-dependent cell death, ferroptosis. This article reviews the current knowledge of iron metabolism, regulators of iron homeostasis, the mechanism of ethanol-induced iron overload, detrimental effects of iron overload in the liver, and potential therapeutic targets.

Synergistic and Detrimental Effects of Alcohol Intake on Progression of Liver Steatosis

Nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) are the most common liver disorders worldwide and the major causes of non-viral liver cirrhosis in the general population. In NAFLD, metabolic abnormalities, obesity, and metabolic syndrome are the driving factors for liver damage with no or minimal alcohol consumption. ALD refers to liver damage caused by excess alcohol intake in individuals drinking more than 5 to 10 daily units for years. Although NAFLD and ALD are nosologically considered two distinct entities, they show a continuum and exert synergistic effects on the progression toward liver cirrhosis. The current view is that low alcohol use might also increase the risk of advanced clinical liver disease in NAFLD, whereas metabolic factors increase the risk of cirrhosis among alcohol risk drinkers. Therefore, special interest is now addressed to individuals with metabolic abnormalities who consume small amounts of alcohol or who binge drink, for the role of light-to-moderate alcohol use in fibrosis progression and clinical severity of the liver disease. Evidence shows that in the presence of NAFLD, there is no liver-safe limit of alcohol intake. We discuss the epidemiological and clinical features of NAFLD/ALD, aspects of alcohol metabolism, and mechanisms of damage concerning steatosis, fibrosis, cumulative effects, and deleterious consequences which include hepatocellular carcinoma.

Effects of Artichoke Supplementation on Liver Enzymes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Studies examining the effect of artichoke on liver enzymes have reported inconsistent results. This systematic review and meta-analysis aimed to assess the effects of artichoke administration on the liver enzymes. PubMed, Embase, the Cochrane Library, and Scopus databases were searched for articles published up to January 2022. Standardized mean difference (Hedges’ g) were analyzed using a random-effects model. Heterogeneity, publication bias, and sensitivity analysis were assessed for the liver enzymes. Pooled analysis of seven randomized controlled trials (RCTs) suggested that the artichoke administration has an effect on both alanine aminotransferase (ALT) (Hedges’ g, −1.08; 95% confidence interval [CI], −1.76 to −0.40; p = 0.002), and aspartate aminotransferase (AST) (Hedges’ g, −1.02; 95% CI, −1.76 to −0.28; p = 0.007). Greater effects on ALT were detected in trials that lasted ≤8 weeks. Also, greater effects on AST were detected in trials using > 500 mg artichoke. Overall, this meta-analysis demonstrated artichoke supplementation decreased ALT and AST.

Metformin Alleviates Hepatic Steatosis and Insulin Resistance in a Mouse Model of High-Fat Diet-Induced Nonalcoholic Fatty Liver Disease by Promoting Transcription Factor EB-Dependent Autophagy

Nonalcoholic fatty liver disease (NAFLD) results from an abnormal accumulation of lipids within hepatocytes, and is commonly associated with obesity, insulin resistance, and hyperlipidemia. Metformin is commonly used to treat type 2 diabetes mellitus and, in recent years, it was found to play a potential role in the amelioration of NAFLD. However, the mechanisms underlying the protective effect of metformin against NAFLD remain largely unknown. Transcription factor EB (TFEB) is a master transcriptional regulator of lysosomal biogenesis and autophagy and, when activated, is effective against disorders of lipid metabolism. However, the role of TFEB in hepatic steatosis is not well understood. In this report, we demonstrate that the activity of TFEB is reduced in the liver of mice fed a high-fat diet. Metformin treatment significantly reverses the activity of TFEB, and the protective effect of metformin against hepatic steatosis and insulin resistance is dependent on TFEB. We show that metformin-induced autophagy is regulated by TFEB, and our findings reveal that TFEB acts as a mediator, linking metformin with autophagy to reverse NAFLD, and highlight that TFEB may be a promising molecular target for the treatment of NAFLD.

Lipid based nanocarriers for effective drug delivery and treatment of diabetes associated liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) is a cluster of several liver diseases like hepatic steatosis, non-alcoholic steatohepatitis (NASH), non-alcoholic fatty liver (NAFL), liver fibrosis, and cirrhosis which may eventually progress to liver carcinoma. One of the primary key factors associated with the development and pathogenesis of NAFLD is diabetes mellitus. The present review emphasizes on diabetes-associated development of liver fibrosis and its treatment using different lipid nanoparticles such as stable nucleic acid lipid nanoparticles, liposomes, solid lipid nanoparticles, nanostructured lipid carriers, self-nanoemulsifying drug delivery systems, and conjugates including phospholipid, fatty acid and steroid-based. We have comprehensively described the various pathological and molecular events linking effects of elevated free fatty acid levels, insulin resistance, and diabetes with the pathogenesis of liver fibrosis. Various passive and active targeting strategies explored for targeting hepatic stellate cells, a key target in liver fibrosis, have also been discussed in detail in this review.

Nonalcoholic Fatty Liver Disease (NAFLD). Mitochondria as Players and Targets of Therapies?

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and represents the hepatic expression of several metabolic abnormalities of high epidemiologic relevance. Fat accumulation in the hepatocytes results in cellular fragility and risk of progression toward necroinflammation, i.e., nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Several pathways contribute to fat accumulation and damage in the liver and can also involve the mitochondria, whose functional integrity is essential to maintain liver bioenergetics. In NAFLD/NASH, both structural and functional mitochondrial abnormalities occur and can involve mitochondrial electron transport chain, decreased mitochondrial β-oxidation of free fatty acids, excessive generation of reactive oxygen species, and lipid peroxidation. NASH is a major target of therapy, but there is no established single or combined treatment so far. Notably, translational and clinical studies point to mitochondria as future therapeutic targets in NAFLD since the prevention of mitochondrial damage could improve liver bioenergetics.

Berbamine induced activation of the SIRT1/LKB1/AMPK signaling axis attenuates the development of hepatic steatosis in high-fat diet-induced NAFLD rats

Non-alcoholic fatty liver disease (NAFLD), a chronic metabolic disorder is concomitant with oxidative stress and inflammation. This study aimed to assess the effects of berbamine (BBM), a natural bisbenzylisoquinoline alkaloid with manifold biological activities and pharmacological effects on lipid, cholesterol and glucose metabolism in a rat model of NAFLD, and to explicate the potential mechanisms underlying its activity. BBM administration alleviated the increase in the body weight and liver index of HFD rats. The aberrations in liver function, serum parameters, and microscopic changes in the liver structure of HFD fed rats were significantly improved upon BBM administration. BBM also significantly attenuated oxidative damage and inhibited triglyceride and cholesterol synthesis. The SIRT1 deacetylase activity was also enhanced by BBM through liver kinase B1 and activated AMP-activated protein kinase. Activation of the SIRT1/LKB1/AMPK pathway prevented the downstream target ACC (acetyl-CoA carboxylase) and elevation in the expression of FAS (fatty acid synthase) and SCD1 (steroyl CoA desaturase). BBM also modulated the expression of PPARs maintaining the fatty acid homeostasis regulation. The assessment of berbamine induced ultrastructural changes by TEM analysis and the expression of autophagic markers LC3a/b, Beclin 1 and p62 revealed the induction of autophagy to alleviate fatty liver conditions. These results show novel findings that BBM induced protection against hepatic lipid metabolic disorders is achieved by regulating the SIRT1/LKB1/AMPK pathway, and thus it emerges as an effective phyoconstituent for the management of NAFLD.

Triglycerides Mediate Body Mass Index and Nonalcoholic Fatty Liver Disease: A Population-Based Study

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is defined by the accumulation of triglycerides (TG). The body mass index (BMI) is associated with NAFLD. This large-scale cohort study was performed to evaluate and quantify the mediating effect of TG on the association between BMI and NAFLD.

METHODS

In total, 15,943 participants in the Kailuan Group were recruited between 2010 and 2014. The impact of TG on the association between BMI and NAFLD was determined through a mediation analysis.

RESULTS

BMI was an independent risk factor for incident NAFLD, with OR of 1.416 (95% CI 1.338-1.499) and 1.187 (95% CI 1.137-1.240) in the low-BMI and high-BMI groups, respectively (p < 0.001). The TG level was a risk factor for NAFLD in the high-BMI group, with an OR of 2.775 (95% CI 1.488-5.177; p = 0.001). Positive associations between BMI and the TG level remained in the 2 above mentioned groups after adjusting for confounders (β = 0.072 and 0.032; p < 0.001). The mediation analysis revealed that TG contributed to 26.050% of incident NAFLD in the high-BMI group (p = 0.01).

CONCLUSION

A high BMI was an independent risk factor for incident NAFLD, and a high TG level was a risk factor in the high-BMI group (BMI ≥24). TG contributes about 25% to incident NAFLD in people with obesity.

Protocols for Mitochondria as the Target of Pharmacological Therapy in the Context of Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is one of the most frequent metabolic chronic liver diseases in developed countries and puts the populations at risk of progression to liver necro-inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma. Mitochondrial dysfunction is involved in the onset of NAFLD and contributes to the progression from NAFLD to nonalcoholic steatohepatitis (NASH). Thus, liver mitochondria could become the target for treatments for improving liver function in NAFLD patients. This chapter describes the most important steps used for potential therapeutic interventions in NAFLD patients, discusses current options gathered from both experimental and clinical evidence, and presents some novel options for potentially improving mitochondrial function in NAFLD.

Benzyl Isothiocyanate Produced by Garden Cress (Lepidium sativum) Prevents Accumulation of Hepatic Lipids

We determined the physiological effects of glucotropaeolin-rich lyophilized garden cress sprout powder (GC) administered to fasting and nonfasting mice. High-performance liquid chromatography analysis revealed glucotropaeolin (57.4±1.1 mg/g dry weight) as a major phytochemical constituent of GC. Decreasing tendency in body weight and feeding efficiency ratio were detected in the group of mice fed 0.05% (w/w) GC (GC0.05). Nonfasting mice exhibited significantly lower liver weights that were unchanged after fasting. Decreased total lipid (TL) and triglyceride (TG) levels in the liver were detected in the nonfasted GC0.01 and GC0.05 groups, but only in TLs of the fasted groups. The levels of plasma TGs and nonesterified fatty acids of the GC0.05 group, which remained unchanged during nonfasting, decreased after fasting. To determine its effects on the accumulation of lipids in the liver, the glucotropaeolin aglycone, benzyl isothiocyanate (BITC), was added to the liver-derived HepG2 human cell line cultured in a medium containing a high concentration of D-glucose (4,500 mg/L D-glucose) (HG group) or 1 mM oleic acid (SO group). Toxicity was not detected when cells were treated with as much as 5 μM BITC; however, lipid accumulation was inhibited by BITC in a concentration-dependent manner in the HG groups. The same effect was observed when 2 μM BITC was added to the diet of the SO groups. These results suggest that moderate levels of GC or BITC are useful for reducing liver and plasma TGs.

Liraglutide modulates gut microbiome and attenuates nonalcoholic fatty liver in db/db mice

AIMS

Liraglutide, a glucagon-like peptide-1(GLP-1) analog, is effective for the treatment of type II diabetes and nonalcoholic fatty liver disease (NAFLD). It was proved that gut microbiome plays a role in the development of NAFLD. This study aims to observe the therapeutic effect of liraglutide on nonalcoholic fatty liver (NAFL) in mice and effect on the gut microbial community.

MAIN METHODS

The db/db mice were used as the NAFL model, and lactulose was used as the positive control drug. Hepatic triglyceride, liver histopathology, and indices of glucolipid metabolism, including fasting blood glucose, fasting insulin, insulin resistance index and blood lipids were evaluated after treatment of liraglutide or lactulose for four weeks. The colonic microbiome of the mice was analyzed by 16S rRNA gene sequencing.

KEY FINDINGS

Liraglutide significantly reduced the hepatic triglyceride (TG) content, alanine aminotransferase (ALT) activity, fasting blood glucose, insulin resistance and serum low density lipoprotein (LDL) in the db/db mice. In terms of hepatic pathologies, hepatic steatosis was significantly improved after liraglutide treating. Microbiome analysis revealed that liraglutide significantly increased the abundance of Akkermansia, Romboutsia, norank_f_Bacteroidales_S24-7_group, and decreased the abundance of Klebsiella, Anaerotruncus, Bacteroides, Lachnospiraceae_UCG-001, Lachnospiraceae_NK4A136_group, Ruminiclostridium, uncultured_f__Ruminococcaceae, and Desulfovibrio.

SIGNIFICANCE

The results of the present study suggested that liraglutide had a certain therapeutic effect on fatty liver in db/db mice and had an impact on the composition of the intestinal microflora, especially some bacteria related to glucolipid metabolism and intestinal inflammation. Affecting gut microbiome might be a potential mechanism of liraglutide in treating NAFL.

Protective Effects of Evogliptin on Steatohepatitis in High-Fat-Fed Mice

There are few studies on the effects of dipeptidyl peptidase-4 inhibitors on steatohepatitis. We explored whether evogliptin (Evo), a dipeptidyl peptidase-4 inhibitor, protects against steatohepatitis in a high-fat diet (HFD)-fed mice and whether these effects involve modulation of mitophagy. Adult male C57BL/J mice were divided into the normal diet (ND), HFD (45% of energy from fat) with Evo (250 mg/kg) (HFD + Evo), and HFD groups at 4 weeks of age and were sacrificed at 20 weeks of age. The HFD group showed hepatic lipid accumulation; this was decreased in the Evo + HFD group. There was an increased 8-hydroxydeoxyguanosine (8-OHDG) expression in the HFD group compared to ND mice. However, 8-OHDG expression levels were significantly decreased in the HFD + Evo group. Expressions of the mitophagy markers PTEN-induced kinase 1 (PINK1), Parkin, and BNIP-3 (BCL2 Interacting Protein 3) were significantly increased in the HFD group. However, the expressions of these markers were lower in the HFD + Evo group than that in the HFD group. Phospho-Akt was upregulated and p53 was downregulated in the HFD + Evo group compared to the HFD group. Evogliptin may alleviate steatohepatitis in HFD-fed mice by ameliorating steatosis and oxidative stress and by modulating mitophagy in the liver.

NRF-2 and nonalcoholic fatty liver disease

Currently, chronic liver diseases have conditioned morbidity and mortality, many of these with a metabolic, toxicologic, immunologic, viral, or other etiology. Thus, a transcription factor that has been of huge importance for biomedical research is NRF-2. The latter is considered a principal component of the antioxidant mechanism, and it has been acknowledged that it impairs the function of NRF-2 in many liver diseases and that it forms an essential part of the pathologic changes that occur in the liver to contain inflammation and damage. Within the investigations and experiments carried out, there are isolated drugs, many of them related to plants and natural extracts that possess antioxidant properties through the NRF-2 signaling pathway, or even involving the stimulation of the transcription target proteins of NRF-2. Notwithstanding all of these experimental findings, to date there is not sufficient clinical evidence to justify the use of NRF-2 in medical practice.

Increased risks of different grades of non-alcoholic fatty liver disease in prediabetic subjects with impaired fasting glucose and glucose tolerance, including the isolated glycosylated hemoglobin levels of 5.7-6.4% in a Chinese population

AIMS/INTRODUCTION

Contrary to the results of the majority of studies on diabetes, there are some conflicting results regarding the relationship between non-alcoholic fatty liver disease (NAFLD) and prediabetes. No study has investigated the relationship between isolated glycated hemoglobin (HbA1c) in the range of 5.7-6.4% (HbA1c 5.7-6.4%) and NAFLD. Our aim was to investigate the effect of different glycemic statuses on NAFLD concomitantly categorized by fasting plasma glucose, 2-h plasma glucose and HbA1c levels.

MATERIALS AND METHODS

NAFLD was classified into three groups by ultrasonographic examination results: normal, mild and moderate-to-severe. Glycemic status was divided into five groups: normoglycemia, isolated HbA1c 5.7-6.4%, impaired fasting glucose without impaired glucose tolerance (IGT), IGT and newly diagnosed diabetes. For multivariable logistic regression analyses, the outcome variable was the classified three grades of fatty changes in the liver after adjusting for other potential risk covariables.

RESULTS

In this cross-sectional research, a total of 8,571 eligible individuals were enrolled and divided into three groups: 5,499 without fatty liver, 2,113 with mild NAFLD and 959 with moderate-to-severe NAFLD. Multivariable logistic regression analysis showed that IGT, impaired fasting glucose without IGT and isolated HbA1c 5.7-6.4% were associated with a higher risk of NAFLD in addition to newly diagnosed diabetes. Other positively predictive variables were male sex, obesity, overweight, central obesity, increased triglyceride and C-reactive protein >1 mg/L. Negatively associated factors were elevated high-density lipoprotein cholesterol levels.

CONCLUSIONS

Besides diabetes, the increased risks of different grades of NAFLD were found for prediabetic individuals categorized by impaired fasting glucose without IGT, IGT and isolated HbA1c 5.7-6.4%.

Hepatic consequences of COVID-19 infection. Lapping or biting?

The outbreak of coronavirus disease 2019 (COVID-19) starting last December in China placed emphasis on liver involvement during infection. This review discusses the underlying mechanisms linking COVID-19 to liver dysfunction, according to recent available information, while waiting further studies. The manifestations of liver damage are usually mild (moderately elevated serum aspartate aminotransferase activities), and generally asymptomatic. Few patients can still develop severe liver problems, and therapeutic options can be limited. Liver dysfunction may affect about one-third of the patients, with prevalence greater in men than women, and in elderly. Mechanisms of damage are complex and include direct cholangiocyte damage and other coexisting conditions such as the use of antiviral drugs, systemic inflammatory response, respiratory distress syndrome-induced hypoxia, sepsis, and multiple organ dysfunction. During new COVID-19 infections, liver injury may be observed. If liver involvement appears during COVID-19 infection, however, attention is required. This is particularly true if patients are older or have a pre-existing history of liver diseases. During COVID-19 infection, the onset of liver damage impairs the prognosis, and hospital stay is longer.

The Controversial Role of Human Gut Lachnospiraceae

The complex polymicrobial composition of human gut microbiota plays a key role in health and disease. Lachnospiraceae belong to the core of gut microbiota, colonizing the intestinal lumen from birth and increasing, in terms of species richness and their relative abundances during the host's life. Although, members of Lachnospiraceae are among the main producers of short-chain fatty acids, different taxa of Lachnospiraceae are also associated with different intra- and extraintestinal diseases. Their impact on the host physiology is often inconsistent across different studies. Here, we discuss changes in Lachnospiraceae abundances according to health and disease. With the aim of harnessing Lachnospiraceae to promote human health, we also analyze how nutrients from the host diet can influence their growth and how their metabolites can, in turn, influence host physiology.

Repeated Administration of Kupffer Cells-Targeting Nanoantioxidant Ameliorates Liver Fibrosis in an Experimental Mouse Model

Kupffer cells are a major producer of reactive oxygen species and have been implicated in the development of liver fibrosis during chronic hepatitis in non-alcoholic steatohepatitis (NASH) and alcoholic steatohepatitis (ASH). We recently reported on the development of a polythiolated and mannosylated human serum albumin (SH-Man-HSA) that functions as a Kupffer cell-targeting nanoantioxidant. In this material, the albumin is mannosylated, which permits it to be taken up by mannose receptor C type 1 expressed on Kupffer cells, and is also polythiolated to have antioxidant activity. To clarify the anti-fibrotic property of this nanoantioxidant, we repeatedly administered SH-Man-HSA to a liver fibrosis mouse model that was induced by the repeated treatment of the concanavalin-A, which mimics the liver fibrosis observed in NASH and ASH. SH-Man-HSA dramatically improved the survival rate and suppressed liver fibrosis in the experimental model. In addition, SH-Man-HSA suppressed hepatic oxidative stress levels, thereby decreasing the numbers of apoptotic cells. In contrast, N-acetylcysteine, which contains the same thiol content as the SH-Man-HSA, failed to show a substantial therapeutic effect in these mice. The expression levels of inflammatory genes including epidermal growth factor module-containing mucin-like receptor (Emr-1/F4/80), Toll-like receptor-4 (TLR-4), high mobility group box-1 (HMGB-1), CC chemokine ligand-5 (CCL-5), tumor necrosis factor-α (TNF-α), CCL-2, interleukin-6 (IL-6), and IL-1β, as well as fibrotic (α-smooth muscle actin (α-SMA), transforming growth factor-β (TGF-β), and Snail) and extracellular matrix genes (collagen, type Iα2 (Col1α2), matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinase 1 (TIMP-1)), showed some decreasing trends by the SH-Man-HSA administration. These findings suggest that the repeated administration of the Kupffer cell-targeting nanoantioxidant, SH-Man-HSA, ameliorates liver fibrosis in mice by suppressing the level of oxidative stress and a portion of the inflammation, and has a potential therapeutic effect against NASH and ASH.

Aquaporin-9 is involved in the lipid-lowering activity of the nutraceutical silybin on hepatocytes through modulation of autophagy and lipid droplets composition

Hepatic steatosis is the hallmark of non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome and insulin resistance with potential evolution towards non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma. Key roles of autophagy and oxidative stress in hepatic lipid accumulation and NAFLD progression are recognized. Here, we employed a rat hepatoma cell model of NAFLD progression made of FaO cells exposed to oleate/palmitate followed or not by TNFα treatment to investigate the molecular mechanisms through which silybin, a lipid-lowering nutraceutical, may improve hepatic lipid dyshomeostasis. The beneficial effect of silybin was found to involve amelioration of the fatty acids profile of lipid droplets, stimulation of the mitochondrial oxidation and upregulation of a microRNA of pivotal relevance in hepatic fat metabolism, miR-122. Silybin was also found to restore the levels of Aquaporin-9 (AQP9) and glycerol permeability while reducing the activation of the oxidative stress-dependent transcription factor NF-κB, and autophagy turnover. In conclusion, silybin was shown to have molecular effects on signaling pathways that were previously unknown and potentially protect the hepatocyte. These actions intersect TG metabolism, fat-induced autophagy and AQP9-mediated glycerol transport in hepatocytes.

Short-term Dietary Interventions for the Management of Nonalcoholic Fatty Liver

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) affects millions of individuals on a global scale and currently no gold standard treatment exists. The risk of developing NAFLD is considerably higher with increasing body mass index. Consequently, weight loss should be recommended to all overweight patients with fatty liver. However, lifestyle interventions, irrespective of weight status, may also influence the condition. The aim herein is to present examples of short-term interventions which assess direct effects of dietary-related components on hepatic steatosis.

METHODS

This review includes studies with short-term dietary-related interventions of up to 16 weeks that evaluate their efficacy in reducing intrahepatic lipid contents (hepatic steatosis). This review primarily focuses on the three main macronutrients: dietary carbohydrates, fats and proteins.

RESULTS

High saturated fat intake and high consumption of carbohydrates, particularly from simple sugars such as fructose are reported as risk factors for hepatic steatosis. Overall, shortterm hypocaloric diets have shown beneficial effects in reducing intrahepatic lipid contents. Macronutrient manipulations such as carbohydrate restriction as well as the consumption of unsaturated fatty acids are also reported to have efficacious effects.

CONCLUSION

This review highlights the different dietary interventions that can influence hepatic steatosis in the short term, illustrating both pro and anti-steatotic effects.

Effect of Weight Reduction on Histological Activity and Fibrosis of Lean Nonalcoholic Steatohepatitis Patient

BACKGROUND AND OBJECTIVES

Weight reduction has evidenced benefit on attenuation of histological activity and fibrosis of nonalcoholic steatohepatitis (NASH), but there is scarcity of data for lean NASH subgroup. We have designed this study to compare the effects of weight reduction on histological activity and fibrosis of lean and non-lean NASH.

METHODS

We have included 20 lean and 20 non-lean histologically proven NASH patients. BMI < 25 kg/m2 was defined as non-lean. Informed consent was taken from each subject. All methods were carried out in accordance with the Declaration of Helsinki. Moderate exercise along with dietary restriction was advised for both groups for weight reduction. After 1 year, 16 non-lean and 15 lean had completed second liver biopsy.

RESULTS

Age, sex, alanine transaminase (ALT), aspartate aminotransferase (AST), gamma-glutamyltrasferase (GGT), Homeostasis model assessment insulin resistance (HOMA-IR), triglyceride and high density lipoprotein (HDL) was similar in both groups. Steatosis, ballooning, lobular inflammation, nonalcoholic fatty liver disease activity score (NAS) and fibrosis was similar in the two groups. In lean/non-lean group, any amount of weight reduction, ≥ 5% weight reduction and ≥ 7% weight reduction was found in respectively 8/11, 5/6 and 2/6 patients. In both lean and non-lean groups, weight reduction of any amount was associated with significant reduction of steatosis, ballooning and NAS, except lobular inflammation and fibrosis. In both groups, weight reduction of ≥ 5% was associated with significant reduction in NAS only. However, significant improvement in NAS was noted with ≥ 7% weight reduction in non-lean group only.

CONCLUSION

Smaller amount of weight reduction had the good benefit of improvement in all the segments of histological activity in both lean and non-lean NASH.

Silibinin ameliorates hepatic lipid accumulation and oxidative stress in mice with non-alcoholic steatohepatitis by regulating CFLAR-JNK pathway

Non-alcoholic steatohepatitis (NASH) is a chronic metabolic syndrome and the CFLAR-JNK pathway can reverse the process of NASH. Although silibinin is used for the treatment of NASH in clinical, its effect on CFLAR-JNK pathway in NASH remains unclear. This study aimed to investigate the effect of silibinin on CFLAR-JNK pathway in NASH models both in vivo and in vitro. The in vivo study was performed using male C57BL/6 mice fed with methionine- choline-deficient diet and simultaneously treated with silibinin for 6 weeks. The in vitro study was performed by using mouse NCTC-1469 cells which were respectively pretreated with oleic acid plus palmitic acid, and adenovirus-down Cflar for 24 h, then treated with silibinin for 24 h. After the drug treatment, the key indicators involved in CFLAR-JNK pathway including hepatic injury, lipid metabolism and oxidative stress were determined. Silibinin significantly activated CFLAR and inhibited the phosphorylation of JNK, up-regulated the mRNA expression of Pparα, Fabp5, Cpt1α, Acox, Scd-1, Gpat and Mttp, reduced the activities of serum ALT and AST and the contents of hepatic TG, TC and MDA, increased the expression of NRF2 and the activities of CAT, GSH-Px and HO-1, and decreased the activities and expression of CYP2E1 and CYP4A in vivo. These effects were confirmed by the in vitro experiments. Silibinin prevented NASH by regulating CFLAR-JNK pathway, and thereby on one hand promoting the β-oxidation and efflux of fatty acids in liver to relieve lipid accumulation, and on the other hand inducing antioxidase activity (CAT, GSH-Px and HO-1) and inhibiting pro-oxidase activity (CYP2E1 and CYP4A) to relieve oxidative stress.

Cold-pressed Canola Oil Reduces Hepatic Steatosis by Modulating Oxidative Stress and Lipid Metabolism in KM Mice Compared with Refined Bleached Deodorized Canola Oil

The quality of canola oil is affected by different extraction methods. The effect of cold-pressed canola oil (CPCO) diet and traditional refined bleached deodorized canola oil (RBDCO) diet on lipid accumulation and hepatic steatosis in mice were investigated. The body weight, peroxisome proliferator-activated receptor-α concentration, serum lipid profile, insulin sensitivity, and oxidative stress were increased in mice fed with CPCO diet, which had higher unsaturated fatty acid, tocopherols, phytosterols, and phospholipids but lower saturated fatty acid than RBDCO, after 12 weeks,. Moreover, CPCO significantly increased tocopherols and phytosterols content in liver and reduced liver cholesterol contents and lipid vacuoles accumulation than RBDCO. Also, serum proinflammatory cytokines, 3-hydroxy-3-methylglutary coenzyme A reductase expression level, lipogenic enzymes, and transcriptional factors such as sterol regulatory element-binding proteins 1c, acetyl-CoA carboxylase, and fatty acid synthase in the liver were also markedly downregulated from CPCO diet mice. Overall, CPCO can reduce lipid accumulation and hepatic steatosis by regulating oxidative stress and lipid metabolism in Kun Ming mice compared with RBDCO. PRACTICAL APPLICATION: The results suggested that more bioactive components were contained in cold-pressed canola oil (CPCO) rather than refined bleached deodorized canola oil (RBDCO). CPCO could lower the risk of obesity and hyperlipidemia, reduce lipid accumulation, and prevent hepatic steatosis. It could be considered as a kind of better edible oil than RBDCO.

Aromatic aldehyde compound cuminaldehyde protects nonalcoholic fatty liver disease in rats feeding high fat diet

Nonalcoholic fatty liver disease (NAFLD) is caused by fat accumulation and is related with obesity and oxidative stress. In this study, we investigated the effect of cuminaldehyde on NAFLD in rats fed a high fat diet (HFD). Male Wistar rats were fed a HFD for 42 days to induce NAFLD. The progression of NAFLD was evaluated by histology and measuring liver enzymes (alanine transaminase and aspartate transaminase), serum and hepatic lipids (total triglycerides and total cholesterol), and oxidative stress markers (thiobarbituric acid reactive substances, glutathione, superoxide dismutase, and catalase). The HFD feeding increased the liver weight and caused NAFLD, liver steatosis, hyperlipidemia, oxidative stress, and elevated liver enzymes. Administration of cuminaldehyde ameliorated the changes in hepatic morphology and liver weight, decreased levels of liver enzymes, and inhibited lipogenesis. Our findings suggest that cuminaldehyde could improve HFD-induced NAFLD via abolishment of hepatic oxidative damage and hyperlipidemia. Cuminaldehyde might be considered as a potential aromatic compound in the treatment of NAFLD and obesity through the modulation of lipid metabolism.

Animal Models of Steatosis (NAFLD) and Steatohepatitis (NASH) Exhibit Hepatic Lobe-Specific Gelatinases Activity and Oxidative Stress

Animal models of obstructive cholestasis and ischemia/reperfusion damage have revealed the functional heterogeneity of liver lobes. This study evaluates this heterogeneity in nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) rat models. Twelve-week-old Obese and Lean male Zucker rats were used for NAFLD. Eight-week-old male Wistar rats fed with 8-week methionine-choline-deficient (MCD) diet and relative control diet were used for NASH. Gelatinase (MMP-2; MMP-9) activity and protein levels, tissue inhibitors of metalloproteinase (TIMPs), reactive oxygen species (ROS), and thiobarbituric acid-reactive substances (TBARS) were evaluated in the left (LL), median (ML), and right liver (RL) lobes. Serum hepatic enzymes and TNF-alpha were assessed. An increase in gelatinase activity in the NASH model occurred in RL compared with ML. TIMP-1 and TIMP-2 displayed the same trend in RL as ML and LL. Control diet RL showed higher MMP-9 activity compared with ML and LL. No significant lobar differences in MMP-2 activity were detected in the NAFLD model. MMP-9 activity was not detectable in Zucker rats. TIMP-1 was lower in LL when compared with ML while no lobar differences were detectable for TIMP-2 in either Obese or Lean Zucker rats. Control diet rats exhibited higher ROS formation in LL versus RL. Significant increases in TBARS levels were observed in LL versus ML and RL in control and MCD rats. The same trend for ROS and TBARS was found in Obese and Lean Zucker rats. An increased serum TNF-alpha occurred in MCD rats. A lobar difference was detected for MMPs, TIMPs, ROS, and TBARS in both MCD and Zucker rats. Higher MMP activation in RL and higher oxidative stress in the LL, compared with the other lobes studied, supports growing evidence for functional heterogeneity among the liver lobes occurring certainly in both NAFLD and NASH rats.

Sulforaphane Improves Lipid Metabolism by Enhancing Mitochondrial Function and Biogenesis In Vivo and In Vitro

SCOPE

Sulforaphane (SFN) is reported to reduce the accumulation of lipids. However, the underling mechanism remains unclear. In this study, the potential of SFN to improve lipid metabolism is investigated through altering mitochondrial function and biogenesis-related mechanisms.

METHODS AND RESULTS

The abnormal lipid metabolism model was established both in HHL-5 cells and in rats by feeding a high-fat diet (HFD) for 10 weeks. The current findings suggest that SFN alleviates the swelling of mitochondria and stimulates mitochondrial biogenesis. The reduced expression of NRF1 and TFAM, were reversed by SFN. SFN increases the levels of antioxidant compounds via nuclear factor erythroid-2-related factor (Nrf2) activation. Furthermore, SFN improves multiple mitochondrial bioactivities, such as mitochondrial membrane potential, ATP, and the electron transfer chain based on PGC-1α pathway. SFN also activates lipolysis by transcriptionally upregulating adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL).

CONCLUSIONS

SFN enhances utilization of lipids via both the PGC- 1α-dependent promotion of mitochondrial biogenesis and Nrf2 dependent improvement of mitochondrial function.

Adiponectin homolog novel osmotin protects obesity/diabetes-induced NAFLD by upregulating AdipoRs/PPARα signaling in ob/ob and db/db transgenic mouse models

BACKGROUND

In metabolic disorders, adiponectin and adiponectin receptors (AdipoR1/R2) signaling has a key role in improving nonalcoholic fatty liver disease (NAFLD) in obesity-associated diabetes.

OBJECTIVE

To the best of our knowledge, here, we reported for the first time the underlying mechanistic therapeutic efficacy of the novel osmotin, a homolog of mammalian adiponectin, against NAFLD in leptin-deficient ob/ob and db/db mice.

METHODS

The ob/ob and db/db mice were treated with osmotin at a dose of 5 μg/g three times a week for two weeks. To co-relate the in vivo results we used the human liver carcinoma HepG2 cells, subjected to knockdown with small siRNAs of AdipoR1/R2 and PPARα genes and treated with osmotin and palmitic acid (P.A.). MTT assay, Western blotting, immunohistofluorescence assays, and plasma biochemical analyses were applied.

RESULTS

Osmotin stimulated AdipoR1/R2 and its downstream APPL1/PPAR-α/AMPK/SIRT1 pathways in ob/ob and db/db mice, and HepG2 cells exposed to P.A. Mechanistically, we confirmed that knockdown of AdipoR1/R2 and PPARα by their respective siRNAs abolished the osmotin activity in HepG2 cells exposed to P.A. Overall, the in vivo and in vitro results suggested that osmotin protected against NAFLD through activation of AdipoR1/R2 and its downstream APPL1/PPAR-α/AMPK/SIRT1 pathways as shown by the reduced body weight, blood glucose level and glycated hemoglobin, improved glucose tolerance, attenuated insulin resistance and hepatic glucogenesis, regulated serum lipid parameters, and increased fatty acid oxidation and mitochondrial functions.

CONCLUSION

Our findings strongly suggest that novel osmotin might be a potential novel therapeutic tool against obesity/diabetes-induced NAFLD and other metabolic disorders.

Targeting mitochondria to oppose the progression of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a condition characterized by the excessive accumulation of triglycerides in hepatocytes. NAFLD is the most frequent chronic liver disease in developed countries, and is often associated with metabolic disorders such as obesity and type 2 diabetes. NAFLD definition encompasses a spectrum of chronic liver abnormalities, ranging from simple steatosis (NAFL), to steatohepatitis (NASH), significant liver fibrosis, cirrhosis, and hepatocellular carcinoma. NAFLD, therefore, represents a global public health issue. Mitochondrial dysfunction occurs in NAFLD, and contributes to the progression to the necro-inflammatory and fibrotic form (NASH). Disrupted mitochondrial function is associated with a decrease in the energy levels and impaired redox balance, and negatively affects cell survival by altering overall metabolism and subcellular trafficking. Such events reduce the tolerance of hepatocytes towards damaging hits, and favour the injurious effects of extra-cellular factors. Here, we discuss the role of mitochondria in NAFLD and focus on potential therapeutic approaches aimed at preserving mitochondrial function.

Jaboticaba peel powder and jaboticaba peel aqueous extract reduces obesity, insulin resistance and hepatic fat accumulation in rats

This study investigated the effects of freeze-dried jaboticaba peel (FJP) and jaboticaba tea (JE) on obesity parameters of diet-induced obese rats. Thirty-six male Wistar rats were distributed into six groups: AIN-93 M feed a normal control diet; HFF (obese control) feed a high-fat and fructose diet; Prevention FJP (P. FJP) and Treatment FJP (T. FJP) feed HFF diet with 2% of FJP powder, for 12 and 6 weeks respectively; Prevention JE (P. JE) and Treatment JE (T. JE) were feed with HFF diet and the water was substituted by JE, for 12 and 6 weeks, respectively. Lipid profile, glucose, adiponectin and leptin were measured. Glucose and insulin tolerance, also pancreatic islet insulin secretion were determined. Liver morphology and fat liver accumulation were evaluated. Results showed that HFF-diet induced weight gain, dyslipidemia, glucose intolerance, insulin resistance and hepatic steatosis. All FJP and JE treatments reduced weight gain, adiposity and improved insulin sensitivity. Twelve weeks supplementation increased HDL-cholesterol and prevented hepatic steatosis. Our results suggest that FJP and JE act as functional foods, being a dietary strategy to prevent or control obesity. FJP and JE 12 weeks supplementation can modulate important parameters of obesity and insulin metabolism, preventing liver steatosis in obese rats.

Gold nanoparticles as cell regulators: beneficial effects of gold nanoparticles on the metabolic profile of mice with pre-existing obesity

Background

We have previously shown that intraperitoneal injection of gold nanoparticles (AuNPs, 20–30 nm) into mice, decreases high-fat diet (HFD) induced weight gain and glucose intolerance, via suppression of inflammatory responses in both fat and liver tissues. This study investigates whether AuNPs provide similar benefit to mice with pre-existing obesity. Male C57BL/6 mice were fed a HFD for 15 weeks. AuNPs (OB-EAu 0.0785 μg/g/day, OB-LAu 0.785 μg/g/day, OB-HAu7.85 μg/g/day, ip) were administered to subgroups of HFD-fed mice over the last 5 weeks. Control group was fed standard chow and administered vehicle injection.

Results

Only the OB-LAu group demonstrated significant weight loss (12%), while all AuNP treated groups showed improved glycaemic control and reduced blood lipid levels. In the fat tissue, mRNA expression of pro-inflammatory markers were unchanged following AuNP treatment, while glucose and lipid metabolic markers were improved in OB-LAu and OB-HAu mice. In the liver, AuNP treatment downregulated inflammatory markers and improved lipid metabolic markers, with marked effects in OB-EAu and OB-LAu groups.

Conclusions

AuNP treatment can improve glucose and fat metabolism in mice with long-term obesity, however weight loss was only observed in a single specific dose regime. AuNP therapy is a promising new technology for managing metabolic disorders in the obese.

Electronic supplementary material

The online version of this article (10.1186/s12951-018-0414-6) contains supplementary material, which is available to authorized users.

Pycnogenol protects against diet-induced hepatic steatosis in apolipoprotein-E-deficient mice

Pycnogenol^R (PYC), a combination of active flavonoids derived from French maritime pine bark, is a natural antioxidant that has various pharmacological activities. Here, we investigated the beneficial effect of PYC on diet-induced hepatic steatosis. Apolipoprotein E (ApoE)-deficient male mice were administered PYC at oral doses of 30 or 100 mg·kg^-1·day^-1 for 2 wk in advance and were then fed a high-cholesterol and -fat diet (HCD) for 8 wk. Biochemical, immunohistochemical, and gene expression analyses were conducted to explore the effect of PYC on lipid metabolism in ApoE-deficient mice on a HCD. Short-term treatment with HCD in ApoE-deficient mice induced hepatic injuries, such as lipid metabolism disorder and hepatic histopathological changes. We found that PYC reduced body weight and the increase of serum lipids that had been caused by HCD. Supplementation of PYC significantly reduced lipid deposition in the liver, as shown by the lowered hepatic lipid content and histopathological lesions. We subsequently detected genes related to lipid metabolism and inflammatory cytokines. The study showed that PYC markedly suppressed the expression of genes related to hepatic lipogenesis, fatty acid uptake, and lipid storage while increasing the lipolytic gene, which thus reduced hepatic lipid content. Furthermore, PYC mainly reduced the expression of inflammatory cytokines and the infiltration of inflammatory cells, which were resistant to the development of hepatic steatosis. These results demonstrate that PYC protects against the occurrence and development of hepatic steatosis and may provide a new prophylactic approach for nonalcoholic fatty liver disease (NAFLD).

Models of non-Alcoholic Fatty Liver Disease and Potential Translational Value: the Effects of 3,5-L-diiodothyronine

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in industrialized countries and is associated with increased risk of cardiovascular, hepatic and metabolic diseases. Molecular mechanisms on the root of the disrupted lipid homeostasis in NAFLD and potential therapeutic strategies can benefit of in vivo and in vitro experimental models of fatty liver. Here, we describe the high fat diet (HFD)-fed rat in vivo model, and two in vitro models, the primary cultured rat fatty hepatocytes or the FaO rat hepatoma fatty cells, mimicking human NAFLD. Liver steatosis was invariably associated with increased number/size of lipid droplets (LDs) and modulation of expression of genes coding for key genes of lipid metabolism such as peroxisome proliferator-activated receptors (Ppars) and perilipins (Plins). In these models, we tested the anti-steatotic effects of 3,5-L-diiodothyronine (T2), a metabolite of thyroid hormones. T2 markedly reduced triglyceride content and LD size acting on mRNA expression of both Ppars and Plins. T2 also stimulated mitochondrial oxidative metabolism of fatty acids. We conclude that in vivo and especially in vitro models of NAFLD are valuable tools to screen a large number of compounds counteracting the deleterious effect of liver steatosis. Because of the high and negative impact of liver steatosis on human health, ongoing experimental studies from our group are unravelling the ultimate translational value of such cellular models of NAFLD.

Study of the Serum Metabolomic Profile in Nonalcoholic Fatty Liver Disease: Research and Clinical Perspectives

In recent years, metabolomics has attracted great scientific attention. The metabolomics methodology might permit a view into transitional phases between healthy liver and nonalcoholic steatohepatitis. Metabolomics can help to analyze the metabolic alterations that play a main role in the progression of nonalcoholic steatohepatitis. Lipid, glucose, amino acid, and bile acid metabolism should be widely studied to understand the complex pathogenesis of nonalcoholic steatohepatitis. The discovery of new biomarkers would be important for diagnosis and staging of liver disease as well as for the assessment of efficacy of new drugs. Here, we review the metabolomics data regarding nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. We analyzed the main studies regarding the application of metabolomics methodology in the complex context of nonalcoholic steatohepatitis, trying to create a bridge from the basic to the clinical aspects.

Linking Nonalcoholic Fatty Liver Disease to Hepatocellular Carcinoma: From Bedside to Bench and Back

Aims and background

Nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC) are two major causes of liver disease worldwide. Epidemiological and clinical data have clearly demonstrated that NAFLD and its associated metabolic abnormalities are a risk factor for HCC. Traditionally, the mechanisms whereby NAFLD acts as a risk for HCC are believed to include replicative senescence of steatotic hepatocytes and compensatory hyperplasia of progenitor cells as a reaction to chronic hepatic injury. Recent years have witnessed significant advances in our understanding of the mechanisms underlying the link between NAFLD and HCC.

Methods

In the present review, we provide an update on the pathophysiological pathways linking NAFLD and its associated metabolic derangements to malignant hepatic transformation, with a special focus on insulin resistance, adipokines, inflammation, and angiogenesis. We will also discuss the potential therapeutic implications that such molecular links carry.

Results

Although treating NAFLD could reduce the risk of malignant hepatic transformation, no long-term studies focusing on this issue have been conducted thus far. Insulin resistance, inflammation as well as derangements in adipokines and angiogenic factors associated with NAFLD are closely intertwined with the risk of developing HCC.

Conclusions

Traditional therapeutic approaches in NAFLD including metformin and statins may theoretically reduce the risk of HCC by acting on common pathophysiological pathways shared by NAFLD and HCC.