Non-alcoholic fatty liver disease and the metabolic syndrome: An update

Non-Alcoholic Fatty Liver Disease May Be a Risk Factor for Liver Metastasis After Radical Surgery for Colorectal Cancer: A Retrospective Study

PURPOSE

Distant metastasis develops in approximately one-third of patients with colorectal cancer (CRC) who undergo radical surgery, and colorectal liver metastasis (CRLM) is the most common form of distant metastasis in CRC. Hepatectomy is the only potentially curative treatment for CRLM, but few patients with metastatic CRC meet the criteria for this radical resection, and the 5-year survival rate is poor. Identifying risk factors for CRLM is critical. Non-alcoholic fatty liver disease (NAFLD) is an independent risk factor for CRC. However, the effect of NAFLD on CRC liver metastasis after radical surgery remains unclear. Therefore, we examined the impact of NAFLD-associated hepatic fibrosis on liver metastasis after radical surgery for CRC.

METHODS

We retrospectively analyzed data from 388 patients who underwent curative surgery for CRC at our hospital between April 2008 and March 2015. The patients' clinical results, surgical procedures, postoperative course, and pathological and survival data were collected from the hospital records. The NAFLD fibrosis score was calculated and used to divide the patients into two groups (NAFLD and non-NAFLD).

RESULTS

Recurrence was observed in 83/388 (21.4%) patients after a mean follow-up of 65.6 ± 15.1 months. Twenty-five patients had liver metastasis: 8 in the NAFLD group (8/45; 17.8%) and 17 in the non-NALFD group (17/343; 5.0%) (p = 0.004). Liver metastasis-free survival was significantly worse in the NAFLD than non-NAFLD group (p < 0.001). NAFLD and cancer stage were independent risk factors for liver metastasis recurrence.

CONCLUSION

NAFLD may be a risk factor for liver metastasis in patients with CRC who undergo curative surgery.

Benefits of Combining Sonchus brachyotus DC. Extracts and Synbiotics in Alleviating Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease, commonly abbreviated to NAFLD, is a pervasive ailment within the digestive system, exhibiting a rising prevalence, and impacting individuals at increasingly younger ages. Those afflicted by NAFLD face a heightened vulnerability to the onset of profound liver fibrosis, cardiovascular complications, and malignancies. Currently, NAFLD poses a significant threat to human health, and there is no approved therapeutic treatment for it. Recent studies have shown that synbiotics, which regulate intestinal microecology, can positively impact glucolipid metabolism, and improve NAFLD-related indicators. Sonchus brachyotus DC., a Chinese herb, exhibits hepatoprotective and potent antioxidant properties, suggesting its potential therapeutic use in NAFLD. Our preclinical animal model investigation suggests that the synergy between Sonchus brachyotus DC. extracts and synbiotics is significantly more effective in preventing and treating NAFLD, compared to the isolated use of either component. As a result, this combination holds the potential to introduce a fresh and encouraging therapeutic approach to addressing NAFLD.

The Role of Choline, Soy Isoflavones, and Probiotics as Adjuvant Treatments in the Prevention and Management of NAFLD in Postmenopausal Women

Nonalcoholic fatty liver disease (NAFLD) is a prevalent condition among postmenopausal women that can lead to severe liver dysfunction and increased mortality. In recent years, research has focused on identifying potential lifestyle dietary interventions that may prevent or treat NAFLD in this population. Due to the complex and multifactorial nature of NAFLD in postmenopausal women, the disease can present as different subtypes, with varying levels of clinical presentation and variable treatment responses. By recognizing the significant heterogeneity of NAFLD in postmenopausal women, it may be possible to identify specific subsets of individuals who may benefit from targeted nutritional interventions. The purpose of this review was to examine the current evidence supporting the role of three specific nutritional factors-choline, soy isoflavones, and probiotics-as potential nutritional adjuvants in the prevention and treatment of NAFLD in postmenopausal women. There is promising evidence supporting the potential benefits of these nutritional factors for NAFLD prevention and treatment, particularly in postmenopausal women, and further research is warranted to confirm their effectiveness in alleviating hepatic steatosis in this population.

The Effect of Bioactive Aliment Compounds and Micronutrients on Non-Alcoholic Fatty Liver Disease

In the current review, we focused on identifying aliment compounds and micronutrients, as well as addressed promising bioactive nutrients that may interfere with NAFLD advance and ultimately affect this disease progress. In this regard, we targeted: 1. Potential bioactive nutrients that may interfere with NAFLD, specifically dark chocolate, cocoa butter, and peanut butter which may be involved in decreasing cholesterol concentrations. 2. The role of sweeteners used in coffee and other frequent beverages; in this sense, stevia has proven to be adequate for improving carbohydrate metabolism, liver steatosis, and liver fibrosis. 3. Additional compounds were shown to exert a beneficial action on NAFLD, namely glutathione, soy lecithin, silymarin, Aquamin, and cannabinoids which were shown to lower the serum concentration of triglycerides. 4. The effects of micronutrients, especially vitamins, on NAFLD. Even if most studies demonstrate the beneficial role of vitamins in this pathology, there are exceptions. 5. We provide information regarding the modulation of the activity of some enzymes related to NAFLD and their effect on this disease. We conclude that NAFLD can be prevented or improved by different factors through their involvement in the signaling, genetic, and biochemical pathways that underlie NAFLD. Therefore, exposing this vast knowledge to the public is particularly important.

Examining dyslipidaemia, metabolic syndrome and liver enzyme levels in patients with prediabetes and type 2 diabetes in population from Hoveyzeh cohort study: A case-control study in Iran

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is among the world's top 10 leading causes of death. Additionally, prediabetes is a major risk factor for diabetes. Identifying diabetes co-occurring disorders can aid in reducing adverse effects and facilitating early detection. In this study, we evaluated dyslipidaemia, metabolic syndrome (MetS), and liver enzyme levels in pre-diabetic and T2DM patients in the Persian cohort compared to a control group.

MATERIALS AND METHODS

In this cross-sectional study, 2259 pre-diabetes, 1664 T2DM and 5840 controls (35-70 years) who were selected from the Hoveyzeh cohort centre were examined. Body mass index, blood pressure, fasting blood glucose (FBG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG) and liver enzymes: γ-glutamyltransferase (GGT), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined using the standard protocols. MetS subjects were also identified based on the National Cholesterol Education Program guidelines.

RESULTS

Prediabetes and T2MD were closely correlated with the lipid profile, MetS, and liver enzymes (ALT, GGT, ALT/AST). MetS increases the risk of T2DM by 12.45 [95% CI: 10.88-14.24] fold, while an increase in ALT/AST ratio increases the risk of T2DM by 3.68 [95% CI: 3.159-4.154] fold. ROC curve analysis also revealed the diagnostic roles of GGT, ALT, AST and the ALT/AST ratio among pre-diabetics, diabetics and the control group. The GGT level corresponds to the highest AUCs (0.685) with the highest sensitivity (70.25%).

CONCLUSIONS

Our results indicated a significant increase in liver enzymes, lipid profile and MetS status in both pre-diabetic and T2MD subjects, with the differences being more pronounced in diabetic individuals. Consequently, on the one hand, these variables may be considered predictive risk factors for diabetes, and on the other hand, they may be used as diagnostic factors. In order to confirm the clinical applications of these variables, additional research is required.

Comprehensive Review of Cardiovascular Disease Risk in Nonalcoholic Fatty Liver Disease

Nonalcoholic Fatty Liver Disease (NAFLD) is a growing global phenomenon, and its damaging effects in terms of cardiovascular disease (CVD) risk are becoming more apparent. NAFLD is estimated to affect around one quarter of the world population and is often comorbid with other metabolic disorders including diabetes mellitus, hypertension, coronary artery disease, and metabolic syndrome. In this review, we examine the current evidence describing the many ways that NAFLD itself increases CVD risk. We also discuss the emerging and complex biochemical relationship between NAFLD and its common comorbid conditions, and how they coalesce to increase CVD risk. With NAFLD's rising prevalence and deleterious effects on the cardiovascular system, a complete understanding of the disease must be undertaken, as well as effective strategies to prevent and treat its common comorbid conditions.

Risk Prevention and Health Promotion for Non-Alcoholic Fatty Liver Diseases (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is a serious clinicopathological condition that is recognized as the most frequent chronic liver disease, affecting 14–30% of the world’s population. The prevalence of NAFLD has rapidly grown and is correlated with the growth in obesity and type 2 diabetes, among other factors. NAFLD often results in long-term complications including cardiovascular disease, liver cirrhosis, and liver fibrosis. This paper provides an updated overview of NAFLD with a focus on epidemiology, etiology, pathophysiology, screening, complications, and pharmacological therapies to identify effective risk prevention and health promotion.

Iodine Images in Dual-energy CT: Detection of Hepatic Steatosis by Quantitative Iodine Concentration Values

Hepatic steatosis is a common condition and an early manifestation of a systemic metabolic syndrome. As of today, there is no broadly accepted method for the diagnosis of hepatic steatosis in contrast-enhanced CT images. This retrospective study evaluates the potential of quantitative iodine values in portal venous phase iodine images in dual-energy CT (DECT) by measuring iodine concentrations in regions of interest (ROI) and analyzing the absolute iodine concentration of the liver parenchyma as well as three different blood-normalized iodine concentrations in a study cohort of 251 patients. An independent two sample t-test (p < 0.05) was used to compare the iodine concentrations of healthy and fatty liver. Diagnostic performance was assessed by ROC (receiver operating characteristic) curve analysis. The results showed significant differences between the average iodine concentration of healthy and fatty liver parenchyma for the absolute and for the blood-normalized iodine concentrations. The study concludes that the iodine uptake of the liver parenchyma is impaired by hepatic steatosis, and that the measurement of iodine concentration can provide a suitable method for the detection of hepatic steatosis in quantitative iodine images. Suitable thresholds of quantitative iodine concentration values for the diagnosis of hepatic steatosis are provided.

Different sites of actions make different responses to thiazolidinediones between mouse and rat models of fatty liver

Therapeutic approach for NAFLD is limited and there are no approved drugs. Pioglitazone (PGZ), a thiazolidinedione (TZD) that acts via peroxisome proliferator activated receptor gamma (PPARγ) is the only agent that has shown consistent benefit and efficacy in clinical trials. However, the mechanism of its therapeutic effect on NAFLD remains unclear. The poor understanding may be due to problems with mouse, a species most used for animal experiments. TZDs exacerbate fatty liver in mouse models while they improve it in rat models like in human patients. Therefore, we compared the effects of TZDs including PGZ and rosiglitazone (RGZ) in ob/ob mice and Lepmkyo/Lepmkyo rats, models of leptin-deficient obesity, and A-ZIP/F-1 mice and seipin knockout (SKO) rats, models of generalized lipodystrophy. Pparg mRNA expression was markedly upregulated in fatty livers of mouse models while it was unchanged in rat models. TZDs exacerbated fatty liver in ob/ob and A-ZIP/F-1 mice, improved it in Lepmkyo/Lepmkyo rats and showed no effect in SKO rats. Gene expression analyses of Pparg and its target gene, Fsp27 revealed that PPARγ in the adipose tissue is the exclusive therapeutic target of TZDs in rats but PPARγ in the liver in addition to the adipose tissue is also a major site of actions for TZDs in mice. Although the response to TZDs in mice is the complete opposite of that in human patients, no report has pointed out the problem with TZD studies using mouse models so far. The present study might provide useful suggestions in research on TZDs.

Pharmacological Exploration of Phenolic Compound: Raspberry Ketone-Update 2020

Raspberry ketone (RK) is an aromatic phenolic compound naturally occurring in red raspberries, kiwifruit, peaches, and apples and reported for its potential therapeutic and nutraceutical properties. Studies in cells and rodents have suggested an important role for RK in hepatic/cardio/gastric protection and as an anti-hyperlipidemic, anti-obesity, depigmentation, and sexual maturation agent. Raspberry ketone-mediated activation of peroxisome proliferator-activated receptor-α (PPAR-α) stands out as one of its main modes of action. Although rodent studies have demonstrated the efficacious effects of RK, its mechanism remains largely unknown. In spite of a lack of reliable human research, RK is marketed as a health supplement, at very high doses. In this review, we provide a compilation of scientific research that has been conducted so far, assessing the therapeutic properties of RK in several disease conditions as well as inspiring future research before RK can be considered safe and efficacious with limited side effects as an alternative to modern medicines in the treatment of major lifestyle-based diseases.

Coleus forskohlii Extract Attenuated the Beneficial Effect of Diet-Treatment on NASH in Mouse Model

Obesity is one of the main causes of non-alcoholic steatohepatitis (NASH), which is associated with impaired liver functions including drug metabolism. Coleus forskohlii extract (CFE) is a popular ingredient of weight loss dietary supplements in Japan. In this study, we examined the effect of CFE on the treatment of NASH. C57BL/6 mice (male, 10-wk-old) were fed a NASH diet (high-fat, low-methionine, and choline-deficient diet) for 12 wk to establish NASH. Then, we examined the effect of 0.5% (w/w) CFE in diet during diet-treatment (change to control diet) and/or treadmill-exercise (45 min at 20 m/min, 5 d/wk) to improve NASH for 3 wk. After experimental period, lipids profiles and liver functional markers in the blood, and hepatic lipid content and major CYP subtype mRNA expression and activity in liver were measured. Diet-treatment, but not exercise decreased liver weight and hepatic lipid contents in NASH induced mice. CFE attenuated the effects of diet-treatment which reduced liver weight, even though body weight and adipose tissue weight were reduced. Further, CFE significantly increased liver microsomal CYP1A1, CYP1A2, CYP2C, and CYP3A activities in each condition, and CYP inductions were greater in diet-treatment group compared to those in exercise group. These results suggest that taking CFE should be avoided during diet-treatment of NASH, especially in patients under medication.

Caffeoylquinic Acid Derivatives of Purple Sweet Potato as Modulators of Mitochondrial Function in Mouse Primary Hepatocytes

Owing to their antioxidant properties, caffeoylquinic acid (CQA)-derivatives could potentially improve the impaired metabolism in hepatic cells, however, their effect on mitochondrial function has not been demonstrated yet. Here, we evaluated the impact of three CQA-derivatives extracted from purple sweet potato, namely 5-CQA, 3,4- and 4,5-diCQA, on mitochondrial activity in primary hepatocytes using an extracellular flux analyzer. Notably, an increase of maximal respiration and spare respiratory capacity were observed when 5-CQA and 3,4-diCQA were added to the system indicating the improved mitochondrial function. Moreover, 3,4-diCQA was shown to considerably increase glycolytic reserve which is a measure of cell capability to respond to an energy demand through glycolysis. Conversely, 4,5-diCQA did not modify mitochondrial activity but increased glycolysis at low concentration in primary hepatocytes. All compounds tested improved cellular capacity to oxidize fatty acids. Overall, our results demonstrated the potential of test CQA-derivatives to modify mitochondrial function in hepatic cells. It is especially relevant in case of dysfunctional mitochondria in hepatocytes linked to hepatic steatosis during obesity, diabetes, and metabolic syndrome.

Hepatic Mediators of Lipid Metabolism and Ketogenesis: Focus on Fatty Liver and Diabetes

BACKGROUND

Diabetes mellitus (DM) is a chronic disorder that it is caused by the absence of insulin secretion due to the inability of the pancreas to produce it (type 1 diabetes; T1DM), or due to defects of insulin signaling in the peripheral tissues, resulting in insulin resistance (type 2 diabetes; T2DM). Commonly, the occurrence of insulin resistance in T2DM patients reflects the high prevalence of obesity and non-alcoholic fatty liver disease (NAFLD) in these individuals. In fact, approximately 60% of T2DM patients are also diagnosed to have NAFLD, and this condition is strongly linked with insulin resistance and obesity. NAFLD is the hepatic manifestation of obesity and metabolic syndrome and includes a spectrum of pathological conditions, which range from simple steatosis (NAFL), non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma. NAFLD manifestation is followed by a series of hepatic lipid deregulations and the main abnormalities are increased triglyceride levels, increased hepatic production of VLDL and a reduction in VLDL catabolism. During the progression of NAFLD, the production of ketone bodies progressively reduces while hepatic glucose synthesis and output increases. In fact, most of the fat that enters the liver can be disposed of through ketogenesis, preventing the development of NAFLD and hyperglycemia.

OBJECTIVE

This review will focus on the pathophysiological aspect of hepatic lipid metabolism deregulation, ketogenesis, and its relevance in the progression of NAFLD and T2DM.

CONCLUSION

A better understanding of the molecular mediators involved in lipid synthesis and ketogenesis can lead to new treatments for metabolic disorders in the liver, such as NAFLD.

Association of the Serum Uric Acid-to-Creatinine Ratio with Nonalcoholic Fatty Liver Disease Diagnosed by Computed Tomography

Background: Although previous studies have suggested that the serum uric acid-to-creatinine ratio (sUA/Cr) is associated with metabolic syndrome, there is limited evidence of a relationship between sUA/Cr and nonalcoholic fatty liver disease (NAFLD). In this study, we investigated the association between sUA/Cr and NAFLD in healthy adults. Methods: A cross-sectional analysis was performed in 778 subjects who participated in a health examination. The participants were divided according to presence of NAFLD, which was determined by abdominal computed tomography (CT). Logistic regression analysis was performed to investigate the variables associated with NAFLD, and an adjusted odds ratio (OR) of sUA/Cr for NAFLD was estimated. Results: sUA/Cr in participants with NAFLD was significantly higher than in those without NAFLD. Multivariate analysis demonstrated significant association between sUA/Cr and NAFLD, and the adjusted OR of sUA/Cr increase of 1 for NAFLD was 1.182. (95% CI: 1.066-1.311). Conclusions: Elevated sUA/Cr was significantly associated with CT-diagnosed NAFLD in healthy adults. sUA/Cr may be a reliable marker for predicting NAFLD. (The Clinical Trial Registration number: 2020-06-002-002).

Nonalcoholic fatty liver disease and colorectal cancer: Correlation and missing links

Nonalcoholic fatty liver disease (NAFLD) is one of the major metabolic diseases that occur in almost one in every four global population, while colorectal cancer (CRC) is one of the leading causes of cancer related deaths in the world. Individuals with pre-existing NAFLD show a higher rate of developing CRC and liver metastasis, suggesting a causal relationship. Interestingly, both of these diseases are strongly associated with obesity, which is also a growing global health concern. In this current review, we will explore scientific findings that demonstrate the relationship between NAFLD, CRC and obesity, as well as the underlying mechanisms. We will also indicate the missing links and knowledge gaps that require more in-depth investigation.

Early life stress reduces voluntary exercise and its prevention of diet-induced obesity and metabolic dysfunction in mice

The development of obesity-related metabolic syndrome (MetS) involves a complex interaction of genetic and environmental factors. One environmental factor found to be significantly associated with MetS is early life stress (ELS). We have previously reported on our mouse model of ELS, induced by neonatal maternal separation (NMS), that displays altered regulation of the hypothalamic-pituitary-adrenal (HPA) axis and increased sensitivity in the urogenital organs, which was attenuated by voluntary wheel running. Here, we are using our NMS model to determine if ELS-induced changes in the HPA axis also influence weight gain and MetS. Naïve (non-stressed) and NMS male mice were given free access to a running wheel and a low-fat control diet at 4-weeks of age. At 16-weeks of age, half of the mice were transitioned to a high fat/sucrose (HFS) diet to investigate if NMS influences the effectiveness of voluntary exercise to prevent diet-induced obesity and MetS. Overall, we observed a greater impact of voluntary exercise on prevention of HFS diet-induced outcomes in naïve mice, compared to NMS mice. Although body weight and fat mass were still significantly higher, exercise attenuated fasting insulin levels and mRNA levels of inflammatory markers in epididymal adipose tissue in HFS diet-fed naïve mice. Only moderate changes were observed in exercised NMS mice on a HFS diet, although this could partially be explained by reduced running distance within this group. Interestingly, sedentary NMS mice on a control diet displayed impaired glucose homeostasis and moderately increased pro-inflammatory mRNA levels in epididymal adipose, suggesting that early life stress alone impairs metabolic function and negatively impacts the therapeutic effect of voluntary exercise.

Cathepsin B deficiency ameliorates liver lipid deposition, inflammatory cell infiltration, and fibrosis after diet-induced nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a severe form of nonalcoholic fatty liver disease characterized by fat accumulation and inflammation in liver. Yet, the mechanistic insight and diagnostic and therapeutic options of NASH remain incompletely understood. This study tested the roles of cysteine protease cathepsin B (CatB) in mouse NASH development. Immunoblot revealed increased liver CatB expression in NASH mice. Fructose-palmitate-cholesterol diet increased body weight gain, liver to body weight ratio, blood fasting glucose, plasma total cholesterol and alanine transaminase levels, and liver triglyceride, but decreased plasma high-density lipoprotein in wild-type mice. All these changes were blunted in CatB-deficient (Ctsb^-/-) mice. In parallel to reduced expression of genes involved in liver lipid transport and lipogenesis, liver CD36, FABP4, and PPARγ protein levels were also significantly decreased in Ctsb^-/- mice, although CatB deficiency did not affect liver gluconeogenesis and fatty acid beta-oxidation-associated gene expression. Mechanistic studies showed that CatB deficiency decreased liver expression of adhesion molecules, inflammatory cytokine, and chemokine, along with reduced liver inflammatory cell infiltration. CatB deficiency also promoted M2 macrophage polarization and reduced liver TGF-β1 signaling and fibrosis. Together, CatB deficiency improves liver function in NASH mice by suppressing de novo lipogenesis and liver inflammation and fibrosis.

The Importance of the Fatty Acid Transporter L-Carnitine in Non-Alcoholic Fatty Liver Disease (NAFLD)

L-carnitine transports fatty acids into the mitochondria for oxidation and also buffers excess acetyl-CoA away from the mitochondria. Thus, L-carnitine may play a key role in maintaining liver function, by its effect on lipid metabolism. The importance of L-carnitine in liver health is supported by the observation that patients with primary carnitine deficiency (PCD) can present with fatty liver disease, which could be due to low levels of intrahepatic and serum levels of L-carnitine. Furthermore, studies suggest that supplementation with L-carnitine may reduce liver fat and the liver enzymes alanine aminotransferase (ALT) and aspartate transaminase (AST) in patients with Non-Alcoholic Fatty Liver Disease (NAFLD). L-carnitine has also been shown to improve insulin sensitivity and elevate pyruvate dehydrogenase (PDH) flux. Studies that show reduced intrahepatic fat and reduced liver enzymes after L-carnitine supplementation suggest that L-carnitine might be a promising supplement to improve or delay the progression of NAFLD.

A comparison of the effects of Stevia extract and metformin on metabolic syndrome indices in rats fed with a high-fat, high-sucrose diet

The beneficial effects of Stevia on metabolic indices have been studied in recent years. However, controversial results emphasize the need for further investigation. We aimed to examine and compare the effects of Stevia's hydroalcoholic extract with two dosages (200, 400 mg/kg) with those of metformin (100 mg/kg) on metabolic syndrome (MetS) indices of rats fed with a high-fat, high-sucrose diet (HFHS). It was found that both Stevia extract and metformin could prevent the adverse effects of a HFHS on lipid profile, liver enzymes, total antioxidant capacity (TAC), and histopathologic factors. Except for the finding that metformin showed a greater potential to alleviate insulin resistance than did Stevia extract, no significant difference was observed between the rats receiving metformin or Stevia extract. In addition, using a high treatment dosage of Stevia extract did not lead to better results than a low dosage. Collectively, the efficacy of Stevia extracts to modify metabolic, oxidative, and histopathological indices in a MetS model was comparable to that of the metformin. PRACTICAL APPLICATIONS: This study was aimed to compare the efficiency of Stevia hydroalcoholic extract with metformin in attenuating MetS abnormalities of rats induced by a high-fat, high-sucrose diet. The results showed the beneficial changes caused due to the administration of Stevia extract on lipid profile, antioxidant capacity, liver enzyme, and liver histopathological indices. The changes were comparable with the results of metformin group. Despite some promising results, further investigation is suggested to evaluate the effectiveness of Stevia extract on human subjects.

DHA substitution overcomes high-fat diet-induced disturbance in the circadian rhythm of lipid metabolism

Disruptions to circadian rhythm have been associated with an increased risk of nonalcoholic fatty liver disease (NAFLD). DHA has been found to affect both circadian rhythm and lipid metabolism. In this study, the relationship between DHA substitution and improvements in lipid metabolism and circadian clock regulation was studied. Male C57BL/6 mice were fed a control, a high fat or a DHA substituted diet for 12 weeks. Biochemical analysis and H&E staining showed that the high-fat diet (HFD) could induce NAFLD, and DHA substitution (AOH) could attenuate NAFLD. The qPCR results showed that the expressions of core clock genes Clock and Bmal1 were significantly higher at zeitgeber (ZT) 0 (7:00 am) than those at ZT12 (7:00 pm) in the control group, while this difference in day and night disappeared in the HFD group, but was observed in the AOH group. Western blotting results indicated that the expressions of rhythm output molecules (RORα and REV-ERBα) and their downstream protein INSIG2 all showed the corresponding circadian changes. SREBP-regulated proteins were significantly increased in the HFD group at both ZT0 and ZT12, but decreased in the AOH group accompanied by the corresponding changes in the protein expressions of HMGCR, LXR, CYP7A1 and CYP27A1. Altogether, HFD can decrease or disrupt circadian rhythm fluctuation by up-regulating the expression of core circadian rhythm genes Clock and Bmal1 at ZT12, and induce metabolic abnormalities through the INSIG2-SREBP pathway regulated by RORα and REV-ERBα. DHA substitution seems to restore circadian rhythm similar to the normal circadian rhythm of "night-high, day-low" through the metabolic pathway regulated by rhythmic nuclear receptors, improving the lipid metabolism rhythm and reducing liver fat.

Comparison of silver nanoparticle-induced inflammatory responses between healthy and metabolic syndrome mouse models

Silver nanoparticles (AgNPs) are utilized in surgical implants and medical textiles, thus providing access to the circulation. While research has been conducted primarily in healthy models, AgNP-induced toxicity evaluations in disease conditions are critical, as many individuals have preexisting conditions. Specifically, over 20% of United States adults suffer from metabolic syndrome (MetS). It was hypothesized that MetS may increase susceptibility to AgNP-mediated toxicity due to induction of differential inflammation and altered biodistribution. Mice were injected with 2 mg/kg AgNPs, and organs assessed for inflammatory gene expression (TNF-α, CXCL1, CXCL2, CCL2, TGF-β, HO-1, IL-4, IL-13), and Ag content. AgNPs were determined to induce differential inflammation in healthy and MetS mice. While AgNP exposure increased TNF-α, CXCL1, TGF-β, HO-1, and IL-4 expression within healthy mouse spleens, MetS-treated animals demonstrated decreased CXCL1, IL-4, and IL-13 expression. Healthy and MetS mice livers exhibited similar inflammatory responses to one another. AgNPs localized primarily to the liver and spleen, although Ag was present in all examined organs. In organs of minor AgNP deposition, such as kidney, gene expression was variable. Induction of inflammatory genes did not correspond with biodistribution, suggesting disease-related variations in AgNP-mediated adverse responses. These findings indicate that disease may influence inflammation and biodistribution, impacting AgNP clinical applications.

Exercise Combats Hepatic Steatosis: Potential Mechanisms and Clinical Implications

Hepatic steatosis, the excess storage of intrahepatic lipids, is a rampant clinical problem associated with the obesity epidemic. Hepatic steatosis is linked to increased risk for insulin resistance, type 2 diabetes, and cardiovascular and advanced liver disease. Accumulating evidence shows that physical activity, exercise, and aerobic capacity have profound effects on regulating intrahepatic lipids and mediating susceptibility for hepatic steatosis. Moreover, exercise can effectively reduce hepatic steatosis independent of changes in body mass. In this perspective, we highlight 1) the relationship between obesity and metabolic pathways putatively driving hepatic steatosis compared with changes induced by exercise; 2) the impact of physical activity, exercise, and aerobic capacity compared with caloric restriction on regulating intrahepatic lipids and steatosis risk; 3) the effects of exercise training (modalities, volume, intensity) for treatment of hepatic steatosis, and 4) evidence for a sustained protection against steatosis induced by exercise. Overall, evidence clearly indicates that exercise powerfully regulates intrahepatic storage of fat and risk for steatosis.

Metformin Attenuates Liver Fat Content: Finding from Schizophrenia Patients with Olanzapine-induced Weight Gain

Objective

This study was performed to evaluate the efficacy of metformin on liver fat content (LFC) in first episode schizophrenia patients with olanzapine-induced weight gain, and the relationship between the change of LFC and the other metabolic indices.

Methods

In a double-blind study, the clinically stable inpatients with first-episode schizophrenia under olanzapine monotherapy who gained more than 7% of their baseline weight were randomly assigned to two groups; one with olanzapine plus metformin (1,000 mg/day) (metformin group) and the other with olanzapine plus placebo (placebo group) for 16 weeks. All patients continued to maintain the original olanzapine dosage. LFC was measured by magnetic resonance imaging at baseline and at the end of 16 weeks, respectively. At the same time, glucose and lipid metabolism, homeostasis model assessment of insulin resistance index (HOMA-IR) were measured respectively, analyzing the correlation between the change value of LFC and other indicators.

Results

Over the 16-week study period, LFC value in metformin group decreased compared with baseline. LFC change across the 16-week treatment period was −2.91% for the metformin group and 0.59% for the placebo group, with a between-group difference of −3.5% (95% confidence interval, −6.08 to −0.93; p = 0.009). Compared to baseline, in the metformin group, triglyceride and HOMA-IR reduced significantly, while high density lipoprotein cholesterol increased significantly at weeks 16. There was positive correlation between LFC changes and triglycerides, HOMA-IR changes significantly.

Conclusion

Metformin can significantly attenuate LFC in schizophrenia patients with olanzapine-induced weight gain. It may be related to the improvement of the part of the glucolipid metabolic indices.

Granulocyte Colony Stimulating Factor Ameliorates Hepatic Steatosis Associated with Improvement of Autophagy in Diabetic Rats

BACKGROUND

We previously reported that the granulocyte colony stimulating factor (G-CSF) ameliorated hepatic steatosis with the enhancement of β-oxidation-related gene expression. However, the mechanisms underlying this process remain unclear. This study aimed to determine whether the improvement of hepatic steatosis by G-CSF was associated with autophagy in a rat model of diabetes.

METHODS

Eight rats were fed a standard diet, and 16 rats were fed high-fat diet (HFD) for 5 weeks. All HFD-fed rats were then injected with streptozotocin (STZ). One week later, HFD rats injected with STZ were randomly treated with either G-CSF (200 μg/kg/day; diabetes mellitus (DM)/G-CSF) or saline (DM/saline) for 5 consecutive days. Four weeks later, serum biochemical and histology analyses were conducted. The expression of autophagy-associated proteins was determined by Western blotting. The mRNA expression of β-oxidation-related genes was determined by quantitative real-time polymerase chain reaction. HepG2 cells were cultured under high glucose (HG) conditions with G-CSF treatment, followed by Oil Red O staining for quantification of lipids.

RESULTS

Histological analysis showed lower lipid accumulation in the DM/G-CSF group than in the DM/saline-treated rats. Protein levels of LC3 and beclin-1 were higher, and those of p62 were lower in the DM/G-CSF rats than in the DM/saline-treated rats. The mRNA expression of β-oxidation-related genes was higher in DM/G-CSF rats than in the DM/saline-treated rats. Quantification of lipid levels in HepG2 cells cultured with HG and G-CSF treatment revealed no significant differences.

CONCLUSIONS

Our data suggested that G-CSF potentially improves hepatic steatosis and autophagy in the liver of diabetic rats.

Physical Activity and Sedentary Time: Association with Metabolic Health and Liver Fat

Introduction/Purpose

To investigate whether (a) lower levels of daily physical activity (PA) and greater sedentary time accounted for contrasting metabolic phenotypes (higher liver fat/presence of metabolic syndrome [METS+] vs lower liver fat/absence of metabolic syndrome [METS−]) in individuals of similar body mass index and (b) the association of sedentary time on metabolic health and liver fat.

Methods

Ninety-eight habitually active participants (53 female, 45 male; age, 39 ± 13 yr; body mass index 26.9 ± 5.1 kg·m⁻²), underwent assessments of PA (SenseWear armband; wear time ~98%), cardiorespiratory fitness (V˙O₂ peak), body composition (magnetic resonance imaging and magnetic resonance spectroscopy) and multiorgan insulin sensitivity (oral glucose tolerance test). We undertook a) cross-sectional analysis comparing four groups: nonobese or obese, with and without metabolic syndrome (METS+ vs METS−) and b) univariate and multivariate regression for sedentary time and other levels of PA in relation to liver fat.

Results

Light, moderate, and vigorous PA did not account for differences in metabolic health between individuals, whether nonobese or obese, although METS+ individuals were more sedentary, with a higher number, and prolonged bouts (~1–2 h). Overall, sedentary time, average daily METS and V˙O₂ peak were each independently associated with liver fat percentage. Each additional hour of daily sedentary time was associated with a 1.15% (95% confidence interval, 1.14%–1.50%) higher liver fat content.

Conclusions

Greater sedentary time, independent of other levels of PA, is associated with being metabolically unhealthy; even in habitually active people, lesser sedentary time, and higher cardiorespiratory fitness and average daily METS is associated with lower liver fat.

Efficacy and Mechanism of Polymerized Anthocyanin from Grape-Skin Extract on High-Fat-Diet-Induced Nonalcoholic Fatty Liver Disease

We investigated the therapeutic potential of polymerized anthocyanin (PA) on a nonalcoholic fatty liver disease (NAFLD) model in mice. C57BL/6 mice were fed a high-fat diet (HFD) for 8 weeks to establish the NAFLD mouse model and randomly divided into four groups: control diet (con), NAFLD mice treated with saline (NAFLD), NAFLD mice treated with PA (PA), and NAFLD mice treated with orlistat (Orlistat) for four weeks. Mice were euthanized at the end of the four weeks. Total cholesterol (TC) and triglyceride (TG) levels were estimated, and pathological changes in the liver, white adipose tissue, and signaling pathways related to lipid metabolism were evaluated. Results revealed that the body, liver, and white fat weight of the NAFLD group was significantly increased compared to that of the con group, while that of the PA group showed significant reduction. NAFLD led to an increase in blood lipids in mice (except for HDL). Conversely, PA effectively reduced TC and LDL-C. Compared to the control group, the degree of steatosis in the mice of PA group was decreased. Moreover, PA also regulated the NAFLD signaling pathway. In agreement with improved lipid deposition, PA supplementation inhibited the activation of inflammatory pathways, depressing oxidative stress through increased antioxidant levels, and increasing β-oxidation to inhibit mitochondrial dysfunction. Taken together, our results demonstrate that PA can improve the liver function of NAFLD mice, regulating blood lipids, reducing liver-fat accumulation, and regulating lipid metabolism.

Activation of G0/G1 switch gene 2 by endoplasmic reticulum stress enhances hepatic steatosis

BACKGROUND

Perturbed endoplasmic reticulum (ER) homeostasis and increased levels of G0/G1 Switch Gene 2 (G0S2) have been documented in animal models with fatty liver disease. In this study, we investigated whether G0S2 is regulated by branch of the unfolded protein response (UPR) and contributes to ER stress-induced hepatic steatosis.

METHODS

We first analyzed G0S2 expression and the state of the three canonical UPR branches in several hepatic steatosis models, tunicamycin-treated C57BL/6J mice and HepG2 cells, where ER homeostasis was perturbed. We pretreated HepG2 cells with tauroursodeoxycholic acid (TUDCA) to validate whether G0S2 was the downstream target of ER stress. Loss or gain function analysis was conducted to identify which UPR branch specifically linked to G0S2 transcription. The transcription mechanism was estimated by luciferase reporter assay and ChIP assay.

RESULTS

Here we showed that the activation of ER stress was accompanied by elevation of G0S2 expression in the occurrence of fatty liver disease. Furthermore, G0S2 was found to be a novel target gene of activating transcription factor 4(ATF4). We also localized one conserved ATF4-binding sequence in the 5' regulatory region of G0S2, which was responsible for transcriptional activating G0S2 by ATF4.

CONCLUSION

G0S2 is regulated by the PERK-eIF2α-ATF4 branch of the UPR and mediates ER stress-induced hepatic steatosis.

Prebiotic and probiotic treatment of nonalcoholic fatty liver disease: a systematic review and meta-analysis

Context

Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent and underdiagnosed comorbidity of many chronic diseases that is associated with altered intestinal bacterial communities. This association has prompted research into alternative treatments aimed at modulating intestinal microbiota. Given the novelty of these treatments, scarce evidence regarding their effectiveness in clinical populations exists.

Objective

This meta-analysis sought to systemically review and quantitatively synthesize evidence on prebiotic, probiotic, and synbiotic therapies for patients with NAFLD in randomized controlled trials.

Data sources

PRISMA guidelines ensured transparent reporting of evidence. PICOS criteria defined the research question for the systematic review. A systematic keyword search in PubMed and EMBASE identified 25 studies: 9 assessed prebiotic, 11 assessed probiotic, and 7 assessed symbiotic therapies for a total of 1309 patients.

Data extraction

Basic population characteristics, the primary variables of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (utilized for NAFLD diagnosis), and the secondary variables of body mass index (BMI), gamma-glutamyl transferase (γ-GT), tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP), total cholesterol, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), and triglyceridges (TAG) were extracted. Pooled effect sizes of these variables were calculated by meta-analysis. No publication bias was identified using Begg's and Egger's tests or Cochrane bias assessment tool.

Results

Meta-analysis indicated that microbial therapies significantly reduced BMI (-0.37 kg/m2; 95% confidence interval [CI], -0.46 to -0.28; P < 0.001), hepatic enzymes (ALT, -6.9 U/L [95%CI, -9.4 to -4.3]; AST, -4.6 U/L [95%CI, -6.6 to -2.7]; γ-GT, -7.9 U/L [95%CI, -11.4 to -4.4]; P < 0.001), serum cholesterol (-10.1 mg/dL 95%CI, -13.6 to -6.6; P < 0.001), LDL-c (-4.5 mg/dL; 95%CI, -8.9 to -0.17; P < 0.001), and TAG (-10.1 mg/dL; 95%CI, -18.0 to -2.3; P < 0.001), but not inflammation (TNF-α, -2.0 ng/mL; [95%CI, -4.7 to 0.61]; CRP, -0.74 mg/L [95%CI, -1.9 to 0.37]). Subgroup analysis by treatment category indicated similar effects of prebiotics and probiotics on BMI and liver enzymes but not total cholesterol, HDL-c, and LDL-c.

Conclusion

This meta-analysis supports the potential use of microbial therapies in the treatment of NAFLD and sheds light on their potential mode of action. Further research into these treatments should consider the limitations of biomarkers currently used for the diagnosis and progression of NAFLD, in addition to the inherent challenges of personalized microbial-based therapies.

Transcriptome Analysis Reveals Differential Expression of Genes Regulating Hepatic Triglyceride Metabolism in Pekin Ducks During Dietary Threonine Deficiency

Dietary threonine (Thr) deficiency increases hepatic triglyceride accumulation in Pekin ducks, which results in fatty liver disease and impairs hepatic function. However, the underlying molecular mechanisms altered by dietary Thr deficiency are still unknown. To identify the underlying molecular changes, 180 one-day-old ducklings were divided into three groups, including Thr deficiency group (Thr-D), Thr sufficiency group (Thr-S), and pair-fed group (Pair-F) that was fed with a Thr-sufficient diet but with reduced daily feed intake. The results showed that feed intake was similar between Thr-D and Pair-F groups, but weight gain rate and final body weight in the Thr-D group were lower than those in the Pair-F group. Feed intake, weight gain, and body weight in Thr-D and Pair-F groups were lower than those in the Thr-S group. The Thr-D diet reduced abdominal fat percentage but increased hepatic triglyceride content when compared with that of the Thr-S and Pair-F groups. The Pair-F reduced hepatic levels of C15:0, C17:0, C18:0, C20:0, C20:4n6, and C22:0 and also reduced total fatty acid, saturated fatty acid, and unsaturated fatty acid content when compared with those of the Thr-D and Thr-S groups. The Thr-D diet increased hepatic content of C6:0, C17:1, C18:3n6, C20:0, C20:1n9, and C22:2, as well as reduced the content of C18:2n6t and C23:0 when compared with those of the Thr-S group. Transcriptome analysis in the liver indicated that the Thr-D diet upregulated genes related to fatty acid and triglyceride synthesis and downregulated genes related to fatty acid oxidation and triglyceride transport. Gene ontology analysis showed that more genes related to lipid metabolism processes and molecular function were differentially expressed in the Thr-D group relative to Thr-S and Pair-F groups than in the Pair-F group relative to the Thr-S group. KEGG pathway analysis showed that differentially expressed genes were enriched in signal transduction, immune, hormone, lipid, and amino acid metabolism pathways. Our findings indicated that the Thr-D diet increased hepatic triglyceride and fatty acid accumulation via increasing fatty acid and triglyceride synthesis and reducing fatty acid oxidation and triglyceride transport. These findings provide novel insights into our understanding of the molecular mechanisms underlying fat accumulation in the liver caused by dietary threonine deficiency.

Gene expressions of de novo hepatic lipogenesis in feline hepatic lipidosis

Objectives

The aim of this study was to evaluate if de novo hepatic lipid synthesis contributes to fatty acid overload in the liver of cats with feline hepatic lipidosis (FHL).

Methods

Lipogenic gene expression of peroxisome proliferator-activated receptor-alpha (PPAR-α), peroxisome proliferator-activated receptor-gamma (PPAR-γ), fatty acid synthase (FASN) and sterol regulatory element-binding factor (SREBF1) were evaluated using quantitative RT-PCR in liver tissue of six cats with FHL and compared with the liver tissue of eight healthy cats.

Results

In liver tissue, PPAR-α, PPAR-γ and FASN mRNA expression levels were not significantly different (P >0.12, P >0.89 and P >0.5, respectively) in the FHL group compared with the control group. SREBF1 gene expression was downregulated around 10-fold in the FHL group vs the control group (P = 0.039).

Conclusions and relevance

The downregulation of SREBF1 in the liver tissue of cats with FHL does not support the hypothesis that de novo lipogenesis in the liver is an important pathway of fatty acid accumulation in FHL.

The FATZO mouse, a next generation model of type 2 diabetes, develops NAFLD and NASH when fed a Western diet supplemented with fructose

BACKGROUND

Metabolic disorders such as insulin resistance, obesity, and hyperglycemia are prominent risk factors for the development of non-alcoholic fatty liver disease (NAFLD)/steatohepatitis (NASH). Dietary rodent models employ high fat, high cholesterol, high fructose, methionine/choline deficient diets or combinations of these to induce NAFLD/NASH. The FATZO mice spontaneously develop the above metabolic disorders and type 2 diabetes (T2D) when fed with a normal chow diet. The aim of the present study was to determine if FATZO mice fed a high fat and fructose diet would exacerbate the progression of NAFLD/NASH.

METHODS

Male FATZO mice at the age of 8 weeks were fed with high fat Western diet (D12079B) supplemented with 5% fructose in the drinking water (WDF) for the duration of 20 weeks. The body weight, whole body fat content, serum lipid profiles and liver function markers were examined monthly along with the assessment of liver histology for the development of NASH. In addition, the effects of obeticholic acid (OCA, 30 mg/kg, QD) on improvement of NASH progression in the model were evaluated.

RESULTS

Compared to normal control diet (CD), FATZO mice fed with WDF were heavier with higher body fat measured by qNMR, hypercholesterolemia and had progressive elevations in AST (~ 6 fold), ALT (~ 6 fold), liver over body weight (~ 2 fold) and liver triglyceride (TG) content (1.4-2.9 fold). Histological examination displayed evidence of NAFLD/NASH, including hepatic steatosis, lobular inflammation, ballooning and fibrosis in FATZO mice fed WDF. Treatment with OCA for 15 weeks in FATZO mice on WDF significantly alleviated hypercholesterolemia and elevation of AST/ALT, reduced liver weight and liver TG contents, attenuated hepatic ballooning, but did not affect body weight and blood TG levels.

CONCLUSION

WDF fed FATZO mice represent a new model for the study of progressive NAFLD/NASH with concurrent metabolic dysregulation.

Obestatin protects and reverses nonalcoholic fatty liver disease and its associated insulin resistance in rats via inhibition of food intake, enhancing hepatic adiponectin signaling, and blocking ghrelin acylation

This study investigated the ameliorative and protective effects of long-term obestatin administration (80 nmol/kg/ intraperitoneal injection (i.p.)) on the pathogenesis of high-fat diet (HFD) induced nonalcoholic fatty liver disease (NAFLD) in rats. Rats (n = 8/group) were divided as control, NAFLD, NAFLD + Simvastatin, NAFLD + obestatin, NAFLD then obestatin, and obestatin then NAFLD. Obestatin co -or post-therapy significantly reduced hepatomegaly and reversed hyperlipidemia, hepatic lipid accumulation, and insulin resistance (IR). Mechanistically obestatin treatments in these rats significantly prevented the increases in final body weights and food intake. Concomitantly, it enhanced circulatory adiponectin levels and hepatic signaling as evident by elevated hepatic protein levels of adiponectin receptors (adipoRII), carnitine palmitoyltransferase-1 (CPT-1), peroxisome proliferator-activated receptor- α (PPAR-α), and phosphor-AMPK (p-AMPK). In addition, obestatin enhanced total circulatory ghrelin levels and significantly increased deacylated ghrelin to acylated ghrelin (DAG/AG) ratio. These data suggest that obestatin reverses and protects against development or progression of NAFLD directly by modulating ghrelin and adiponectin signaling or indirectly by lowering food intake.

Sodium acetate improves disrupted glucoregulation and hepatic triglyceride content in insulin-resistant female rats: involvement of adenosine deaminase and dipeptidyl peptidase-4 activities

Combined oral contraceptive (COC) treatment has been shown to be associated with glucose deregulation and increased triglyceride levels, but the mechanisms are elusive. Soluble dipeptidyl peptidase-4 (sDPP-4) and adenosine deaminase (ADA) are involved in the initiation and/or progression of cardiometabolic disorders. We therefore, hypothesized that increased DPP-4 and ADA activities are involved in glucose deregulation and hepatic triglyceride accumulation induced by COC treatment. This study also investigated whether short-chain fatty acid, acetate, would protect against COC-induced dysmetabolic effects. Female Wistar rats received (p.o.) vehicle and COC (1.0 μg ethinylestradiol plus 5.0 μg levonorgestrel) with or without sodium acetate (ACE; 200 mg) for 8 weeks. Treatment with COC led to increased plasma triglyceride-glucose index, 1-h postload glucose response, insulin, free fatty acid, insulin resistance, and impaired glucose tolerance. COC treatment also resulted in increased plasma and hepatic triglycerides (TG), TG/HDL-cholesterol ratio, malondialdehyde, uric acid, lactate dehydrogenase, DPP-4, ADA, and xanthine oxidase (XO) activities. On the other hand, COC led to reduction in nitric oxide level. However, ACE significantly ameliorated the alterations induced by COC treatment, but XO activity remains elevated during COC treatment. This result also demonstrates that increased DPP-4 and ADA activities are at least in part involved in glucose deregulation and hepatic TG accumulation induced by COC treatment. Therefore, sodium acetate would impact positively on cardiometabolic disorders, at least in part, by inhibition of DPP-4 and ADA activities.

Analysis of Time-Series Gene Expression Data to Explore Mechanisms of Chemical-Induced Hepatic Steatosis Toxicity

Non-alcoholic fatty liver disease (NAFLD) represents a wide spectrum of disease, ranging from simple fatty liver through steatosis with inflammation and necrosis to cirrhosis. One of the most challenging problems in biomedical research and within the chemical industry is to understand the underlying mechanisms of complex disease, and complex adverse outcome pathways (AOPs). Based on a set of 28 steatotic chemicals with gene expression data measured on primary hepatocytes at three times (2, 8, and 24 h) and three doses (low, medium, and high), we identified genes and pathways, defined as molecular initiating events (MIEs) and key events (KEs) of steatosis using a combination of a time series and pathway analyses. Among the genes deregulated by these compounds, the study highlighted OSBPL9, ALDH7A1, MYADM, SLC51B, PRDX6, GPAT3, TMEM135, DLGDA5, BCO2, APO10LA, TSPAN6, NEURL1B, and DUSP1. Furthermore, pathway analysis indicated deregulation of pathways related to lipid accumulation, such as fat digestion and absorption, linoleic and linolenic acid metabolism, calcium signaling pathway, fatty acid metabolism, peroxisome, retinol metabolism, and steroid metabolic pathways in a time dependent manner. Such transcription profile analysis can help in the understanding of the steatosis evolution over time generated by chemical exposure.

NAFLD and cardiovascular disease

Nonalcoholic fatty liver disease (NAFLD) is an important cause of chronic hepatic disease and liver transplant in Western societies. The increasing prevalence is related to dietary changes and sedentarism and follows the increasing frequency of obesity and type 2 diabetes mellitus.

Growing evidence of association of NAFLD with cardiovascular diseases (CVD), independent of cardiovascular risk factors, has prompted the clarification of whether the liver is mainly a key-effector or a target-organ of the metabolic disarrangements in the metabolic syndrome. The therapeutic strategies able to alter liver disease progression and, through this, reduce the cardiovascular risk have also been tested in the last 2 decades.

This review focus on the possible interactions between hepatic disease, metabolic syndrome, and CVD, and on their implications for clinical practice.

Possible mechanisms underlying fatty liver in a rat model of male hypogonadism: A protective role for testosterone

AIMS

To investigate the effects of testosterone (Test) deficiency and testosterone replacement therapy (TRT) on the development of non-alcoholic fatty liver disease (NAFLD) and associated peripheral insulin resistance (IR) in male rats and to illustrate the underlying mechanisms of action.

MATERIALS AND METHODS

male Sprague Dawley rats were divided into 3 groups as follows: 1) sham-operated group (n = 11), 2) ORCD-induced group (n = 9) exposed to orchidectomy (ORCD), achieved by complete surgical removal of testicles, and 3) ORCD + Test treated group (n = 10) (11 ng/mL Test propionate, 3x/week, S.C.).

RESULTS

Data revealed significant increases in final body, liver, visceral and subcutaneous fats weights with significant increases in fasting plasma glucose and insulin levels and HOMA-IR. Additionally, ORCD rats had higher UAC for measured glucose levels and insulin levels during OGTT and higher AUC for measured glucose levels during ITT. Interesting, higher serum and hepatic levels of TGs and CHOL and higher serum levels of LDL were seen in ORCD-induced rats. Mechanistically, significant increases in mRNA levels of SREBP-1, SREBP-2, ACC-1, FAS, HMGCOAR and HMGCOAS with significant increases in protein levels of both precursor and mature SREBP-1 and SREBP-2, PPAR-α, p-PPAR-α, CPT-1 and UCP-2 and significant lower protein levels p-AMPK and p-ACC-1 were detected in livers of ORCD rats. Test administration to ORCD-induced rats significantly ameliorated all of the above mentioned biochemical endpoints and reversed the effect of ORCD on mRNA and protein levels of these targets. In conclusion, Test deficiency could be an independent risk factor for the development of NAFLD by upregulation of lipid synthesis and disturb fatty acids oxidation whereas Test therapy is a protective strategy.

Neonatal intake of oleanolic acid attenuates the subsequent development of high fructose diet-induced non-alcoholic fatty liver disease in rats

Dietary manipulations during the early postnatal period are associated with the development of metabolic disorders including non-alcoholic fatty liver disease (NAFLD) or long-term protection against metabolic dysfunction. We investigated the potential hepatoprotective effects of neonatal administration of oleanolic acid (OA), a phytochemical, on the subsequent development in adulthood, of dietary fructose-induced NAFLD. Male and female suckling rats (n=112) were gavaged with; distilled water (DW), OA (60 mg/kg), high fructose solution (HF; 20% w/v) and OA+HF (OAHF) for 7 days. The rats were weaned onto normal rat chow on day 21 up to day 55. From day 56, half of the rats in each treatment group were continued on plain water or HF as drinking fluid for 8 weeks. Hepatic lipid accumulation and hepatic histomorphometry were then determined. Fructose consumption in adulthood following neonatal fructose intake (HF+F) caused a 47-49% increase in hepatic lipid content of both male and female rats (P<0.05). However, fructose administered in adulthood only, caused a significant increase (P<0.05) in liver lipid content in females only. NAFLD activity scores for inflammation and steatosis were higher in the fructose-fed rats compared with other groups (P<0.05). Steatosis, low-grade inflammation and fibrosis were observed in rats that received HF+F. NAFLD area fraction for fibrosis was three times higher in rats that received fructose neonatally and in adulthood compared with the rats in the negative control group (P<0.05). Treatment with OA during a critical window of developmental plasticity in rats prevented the development of fructose-induced NAFLD.

Variations of the liver standardized uptake value in relation to background blood metabolism: An 2-[18F]Fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography study in a large population from China

To investigate the influence of background blood metabolism on liver uptake of 2-[F]fluoro-2-deoxy-D-glucose (F-FDG) and search for an appropriate corrective method.Positron emission tomography/computed tomography (PET/CT) and common serological biochemical tests of 633 healthy people were collected retrospectively. The mean standardized uptake value (SUV) of the liver, liver artery, and portal vein (i.e., SUVL, SUVA, and SUVP) were measured. SUVL/A was calculated as SUVL/SUVA, while SUVL/P was calculated as SUVL/SUVP. SUV of liver parenchyma (SUVLP) was calculated as SUVL - .3 × (.75 × SUVP + .25 × SUVA). The coefficients of variation (CV) of SUVL, SUVL/A, SUVL/P, and SUVLP were compared to assess their interindividual variations. Univariate and multivariate analyses were performed to identify vulnerabilities of these SUV indexes to common factors assessed using serological liver functional tests.SUVLP was significantly larger than SUVL (2.19 ± .497 vs 1.88 ± .495, P < .001), while SUVL/P was significantly smaller than SUVL (1.72 ± .454 vs 1.88 ± .495, P < .001). The difference between SUVL/A and SUVL was not significant (1.83 ± .500 vs 1.88 ± .495, P = .130). The CV of SUVLP (22.7%) was significantly smaller than that of SUVL (22.7%:26.3%, P < .001), while the CVs of SUVL/A (27.2%) and SUVL/P (26.4%) were not different from that of SUVL (P = .429 and .929, respectively). Fewer variables independently influenced SUVLP than influenced SUVL, SUVL/A, and SUVL/P; Only aspartate aminotransferase, body mass index, and total cholesterol, all P-values <.05.The activity of background blood influences the variation of liver SUV. SUVLP might be an alternative corrective method to reduce this influence, as its interindividual variation and vulnerability to effects from common factors of serological liver functional tests are relatively lower than the commonly used SUVL.

Ellagic Acid Alleviates Hepatic Oxidative Stress and Insulin Resistance in Diabetic Female Rats

Non-alcoholic fatty liver disease (NAFLD) affects more than 70% of patients with type 2 diabetes mellitus (T2DM) and has become one of the most common metabolic liver diseases worldwide. To date, treatments specifically targeting NAFLD do not exist. Oxidative stress and insulin resistance have been implicated in the pathogenesis of NAFLD in diabetes. Accordingly, the goal of this present study was to determine whether Ellagic acid (EA), a natural antioxidant polyphenol found in berries and nuts, mitigates hepatic oxidative stress and insulin resistance in T2DM rats, and thus alleviates NAFLD. Using adult female Goto Kakizaki (GK) rats, a non-obese and spontaneous model of T2DM, we found that EA treatment significantly lowered fasting blood glucose and reduced insulin resistance, as shown by a 21.8% reduction in the homeostasis model assessment index of insulin resistance (HOMA-IR), while triglyceride and total cholesterol levels remained unchanged. Increased hepatic lipid accumulation and oxidative stress present in diabetic GK rats was markedly reduced with EA treatment. This effect was associated with a downregulation of the NADPH oxidase subunit, p47-phox, and overexpression of NF-E2-related factor-2 (NRF2). Moreover, EA was able to decrease the hepatic expression of hypoxia-inducible factor (HIF-&alpha;), a transcription factor linked to hypoxia and hepatic steatosis. We further showed that EA treatment activated an insulin signaling pathway in the liver, as evidenced by increased levels of phosphorylated Akt (Ser 473). In conclusion, our results demonstrate that EA diminishes blood glucose levels and potently suppress NAFLD in diabetic rats via mechanisms that involve reductions in p47-phox and HIF-&alpha;, upregulation of NRF2 and enhancement of the Akt signaling pathway in the liver. Together, these results reveal that EA improves hepatic insulin sensitivity and lipid metabolism as a result of its antioxidant effects. This implies an anti-diabetic effect of EA with beneficial effects for the treatment of hepatic complications in T2DM.

Effect of Roux-en-Y gastric bypass on liver mitochondrial dynamics in a rat model of obesity

Bariatric surgery provides significant and durable improvements in glycemic control and hepatic steatosis, but the underlying mechanisms that drive improvements in these metabolic parameters remain to be fully elucidated. Recently, alterations in mitochondrial morphology have shown a direct link to nutrient adaptations in obesity. Here, we evaluate the effects of Roux-en-Y gastric bypass (RYGB) surgery on markers of liver mitochondrial dynamics in a diet-induced obesity Sprague-Dawley (SD) rat model. Livers were harvested from adult male SD rats 90-days after either Sham or RYGB surgery and continuous high-fat feeding. We assessed expression of mitochondrial proteins involved in fusion, fission, mitochondrial autophagy (mitophagy) and biogenesis, as well as differences in citrate synthase activity and markers of oxidative stress. Gene expression for mitochondrial fusion genes, mitofusin 1 (Mfn1; P < 0.05), mitofusin 2 (Mfn2; P < 0.01), and optic atrophy 1 (OPA1; P < 0.05) increased following RYGB surgery. Biogenesis regulators, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α; P < 0.01) and nuclear respiratory factor 1 (Nrf1; P < 0.05), also increased in the RYGB group, as well as mitophagy marker, BCL-2 interacting protein 3 (Bnip3; P < 0.01). Protein expression for Mfn1 (P < 0.001), PGC1α (P < 0.05), BNIP3 (P < 0.0001), and mitochondrial complexes I-V (P < 0.01) was also increased by RYGB, and Mfn1 expression negatively correlated with body weight, insulin resistance, and fasting plasma insulin. In the RYGB group, citrate synthase activity was increased (P < 0.02) and reactive oxygen species (ROS) was decreased compared to the Sham control group (P < 0.05), although total antioxidant capacity was unchanged between groups. These data are the first to show an association between RYGB surgery and improved markers of liver mitochondrial dynamics. These observed improvements may be related to weight loss and reduced energetic demand on the liver, which could facilitate normalization of glucose homeostasis and protect against hepatic steatosis.

Role of 3-Hydroxy Fatty Acid-Induced Hepatic Lipotoxicity in Acute Fatty Liver of Pregnancy

Acute fatty liver of pregnancy (AFLP), a catastrophic illness for both the mother and the unborn offspring, develops in the last trimester of pregnancy with significant maternal and perinatal mortality. AFLP is also recognized as an obstetric and medical emergency. Maternal AFLP is highly associated with a fetal homozygous mutation (1528G>C) in the gene that encodes for mitochondrial long-chain hydroxy acyl-CoA dehydrogenase (LCHAD). The mutation in LCHAD results in the accumulation of 3-hydroxy fatty acids, such as 3-hydroxy myristic acid, 3-hydroxy palmitic acid and 3-hydroxy dicarboxylic acid in the placenta, which are then shunted to the maternal circulation leading to the development of acute liver injury observed in patients with AFLP. In this review, we will discuss the mechanistic role of increased 3-hydroxy fatty acid in causing lipotoxicity to the liver and in inducing oxidative stress, mitochondrial dysfunction and hepatocyte lipoapoptosis. Further, we also review the role of 3-hydroxy fatty acids in causing placental damage, pancreatic islet β-cell glucolipotoxicity, brain damage, and retinal epithelial cells lipoapoptosis in patients with LCHAD deficiency.

Gender-related association between uric acid, homocysteine, γ-glutamyltransferase, inflammatory biomarkers and metabolic syndrome in subjects affected by obesity

AIM

Evaluation of gender-related differences in uric acid (UA), homocysteine and inflammatory biomarkers as metabolic syndrome (MetS) determinants.

PATIENTS & METHODS

Anthropometric and routine data were obtained from 825 obese subjects (591 F, mean age 54 ± 14 years).

RESULTS

Hyperuricemia was 24% in both genders. Waist circumference, creatinine, triglycerides, C-reactive protein and γ-glutamyltransferase were identified as UA-independent determinants in females and creatinine and insulin in males. Hyperuricemia increased MetS risk in both genders (2.8-fold and 1.5-fold in males and females).

CONCLUSION

UA and γ-glutamyltransferase positively relate to MetS in both genders, although inflammatory abnormalities are closer related to UA and MetS in females. These differences in gender physiology may account for epidemiologic gender disparities and help to develop gender-targeted clinical strategies.

Estimating the survival advantage based on telomere length and serum biomarkers of aging

Background

This study aimed to establish a model that estimates the survival advantage at the molecular level based on telomere length and serum biomarkers of aging, to explore clinical significance.

Methods

The study consisted of 100 healthy subjects and 40 type 2 diabetes mellitus patients, 20–90 years of age. Saliva telomere relative length (LnTL) was measured by the quantitative real-time polymerase chain reaction and the serum biochemical parameters, including albumin (ALB), total proteins, total cholesterol, triglycerides, and some enzyme parameters were detected by a biochemical analyzer. The Z values were transformed from mean values and standard deviations to estimate the survival advantage. A normal reference range (95% confidence interval) was set to the comprehensive advantage of the Z values (Z_s) to evaluate the comprehensive survival advantage.

Results

The Z values of serum ALB and saliva LnTL could be used to estimate the survival advantage, and effectively distinguish between the aging and nonaging individuals. The Z_s was greater than 1.64 in the normal reference range, and type 2 diabetes mellitus patients had lower survival advantages compared to those of the control group (p < 0.05).

Conclusions

Our two-dimensional model system using ALB and LnTL was valid and may have potential applications for evaluating the aging status at the molecular level, and for the observation of disease characteristics.