Nonalcoholic Fatty liver disease and obesity

Biomarkers of Hepatic Toxicity: An Overview

Background

Hepatotoxicity is the foremost issue for clinicians and the primary reason for pharmaceutical product recalls. A biomarker is a measurable and quantifiable attribute used to evaluate the efficacy of a treatment or to diagnose a disease. There are various biomarkers which are used for the detection of liver disease and the intent of liver damage.

Objective

This review aims to investigate the current state of hepatotoxicity biomarkers and their utility in clinical settings. Using hepatic biomarkers, the presence of liver injury, its severity, prognosis, causative agent, and type of hepatotoxicity can all be determined.

Methods

Relevant published articles up to 2022 were systematically retrieved from MEDLINE/PubMed, SCOPUS, EMBASE, and WOS databases using keywords such as drug toxicity, hepatotoxicity biomarkers, biochemical parameters, and nonalcoholic fatty liver disease.

Results

In clinical trials and everyday practice, biomarkers of drug-induced liver injury are essential for spotting the most severe cases of hepatotoxicity. Hence, developing novel biomarker approaches to enhance hepatotoxicity diagnosis will increase specificity and/or identify the person at risk. Importantly, early clinical studies on patients with liver illness have proved that some biomarkers such as aminotransferase, bilirubin, albumin, and bile acids are even therapeutically beneficial.

Conclusions

By assessing the unique signs of liver injury, health care professionals can rapidly and accurately detect liver damage and evaluate its severity. These measures contribute to ensuring prompt and effective medical intervention, hence reducing the risk of long-term liver damage and other major health concerns.

Influence of Weight and Body Size on the Pharmacokinetics of Heart Failure Pharmacotherapy: A Systematic Review

OBJECTIVE

To conduct a review of studies evaluating the influence of body size and weight (WT) on the pharmacokinetics (PK) of drugs recommended for heart failure (HF) treatment.

DATA SOURCES

A systematic search of the MEDLINE (1946 to April 2023) and EMBASE (1974 to April 2023) databases was conducted for articles that focused on the impact of WT or body size on the PK of drugs of interest used in HF patients.

STUDY SELECTION AND DATA EXTRACTION

Articles written in English or French related to the aim of our study were retained for analysis.

DATA SYNTHESIS

Of 6493 articles, 20 were retained for analysis. Weight was associated with the clearance of digoxin, carvedilol, enalapril, and candesartan as well as the volume of distribution of eplerenone and bisoprolol. There was no documented direct impact of WT on the PK of furosemide, valsartan, and metoprolol, although these studies were limited or confounded by the small sample size, adjustment of PK factors by WT, or the use of the Cockroff-Gault equation for the evaluation of creatinine clearance, which includes WT.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review highlights and summarizes the available data on the importance of WT on the PK of HF treatment.

CONCLUSION

Considering the significant impact of WT on most HF drugs in this review, it may be important to further investigate it in the context of personalized therapy, particularly in patients presenting extreme WTs.

Obesity and its Relationship with Covid-19: A Review of the Main Pharmaceutical Aspects

Important physiological changes are observed in patients with obesity, such as intestinal permeability, gastric emptying, cardiac output, and hepatic and renal function. These differences can determine variations in the pharmacokinetics of different drugs and can generate different concentrations at the site of action, which can lead to sub therapeutic or toxic concentrations. Understanding the physiological and immunological processes that lead to the clinical manifestations of COVID-19 is essential to correlate obesity as a risk factor for increasing the prevalence, severity, and lethality of the disease. Several drugs have been suggested to control COVID- 19 like Lopinavir, Ritonavir, Ribavirin, Sofosbuvir, Remdesivir, Oseltamivir, Oseltamivir phosphate, Oseltamivir carboxylate, Hydroxychloroquine, Chloroquine, Azithromycin, Teicoplanin, Tocilizumab, Anakinra, Methylprednisolone, Prednisolone, Ciclesonide and Ivermectin. Similarly, these differences between healthy people and obese people can be correlated to mechanical factors, such as insufficient doses of the vaccine for high body mass, impairing the absorption and distribution of the vaccine that will be lower than desired or can be linked to the inflammatory state in obese patients, which can influence the humoral immune response. Additionally, different aspects make the obese population more prone to persistent symptoms of the disease (long COVID), which makes understanding these mechanisms fundamental to addressing the implications of the disease. Thus, this review provides an overview of the relationship between COVID-19 and obesity, considering aspects related to pharmacokinetics, immunosuppression, immunization, and possible implications of long COVID in these individuals.

The effect of cinnamon supplementation on liver enzymes in adults: A systematic review and meta-analysis of randomized controlled trials

AIMS

The aim of this study was to perform a systematic review and meta-analysis of randomized controlled trials (RCTs) to examine the effect of cinnamon supplementation on liver enzymes.

METHODS

A systematic search was performed in electronic databases including PubMed-Medline, Scopus, and ISI Web of Science up to November 2020. We used a random effects model to estimate pooled effect size of alanine aminotransferase (ALT), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) levels.

RESULTS

Seven RCTs (9 treatment arms) fulfilled the eligibility criteria of the present meta-analysis. Overall, meta-analysis could not show any beneficial effect of cinnamon supplementation on AST, ALT, and ALP. Subgroup analyses showed that the effect of cinnamon supplementation on ALT was significant at the dosages of <1500 mg/day (Hedges's: -0.61; 95 % CI: -1.11, -0.10; P = 0.002), in trials lasting>12 weeks (Hedges's: -0.83; 95 % CI: -1.36, -0.30; P = 0.01), and in trials conducted of both gender (Hedges's: -0.72; 95 % CI: -1.45, -0.01; P = 0.04).

CONCLUSION

In summary, cinnamon supplementation had no significant effect on liver enzymes in adults. However, the effect of cinnamon on ALT levels was significant at the dosages of <1500 mg/day, in trials lasting>12 weeks, and in trials conducted of both gender. Nevertheless, further studies should be performed to confirm our results.

The potential ameliorative impacts of cerium oxide nanoparticles against fipronil-induced hepatic steatosis

Fipronil (FIP) is a phenylpyrazole insecticide that is commonly used in agricultural and veterinary fields for controlling a wide range of insects, but it is a strong environmentally toxic substance. Exposure to FIP has been reported to increase the hepatic fat accumulation through altered lipid metabolism, which ultimately can contribute to nonalcoholic fatty liver disease (NAFLD) development. The present study aimed to examine the function of cerium oxide nanoparticles (CeNPs) in protecting against hepatotoxicity and lipogenesis induced by FIP. Twenty-eight male albino rats were classified into four groups: FIP (5 mg/kg/day per os), CTR, CeNPs (35 mg/kg/day p.o.), and FIP + CeNPs (5 (FIP) + 35 (CeNPs) mg/kg/day p.o.) for 28 consecutive days. Serum lipid profiles, hepatic antioxidant parameters and pathology, and mRNA expression of adipocytokines were assessed. The results revealed that FIP increased cholesterol, height-density lipoprotein, triacylglyceride, low-density lipoprotein (LDL-c), and very-low-density lipoprotein (VLDL-c) concentrations. It also increased nitric oxide (NO) and malondialdehyde (MDA) hepatic levels and reduced glutathione peroxidase (GPx) and superoxide dismutase (SOD) enzyme activities. Additionally, FIP up-regulated the fatty acid-binding protein (FABP), acetyl Co-A carboxylase (ACC1), and peroxisome proliferator-activated receptor-alpha (PPAR-α). Immunohistochemically, a strong proliferation of cell nuclear antigen (PCNA), ionized calcium-binding adapter molecule 1 (Iba-1), cyclooxygenase-2 (COX-2) reactions in the endothelial cells of the hepatic sinusoids, and increased expression of caspase3 were observed following FIP intoxication. FIP also caused histological changes in hepatic tissue. The CeNPs counteracted the hepatotoxic effect of FIP exposure. So, this study recorded an ameliorative effect of CeNPs against FIP-induced hepatotoxicity.

Pfeifer-Weber-Christian Disease: A Case Report and Review of Literature on Visceral Involvements and Treatment Choices

Pfeifer-Weber-Christian disease (PWCD) is a rare idiopathic disease characterized by lobular panniculitis of adipose tissue with systemic symptoms and multiple organ involvement. Even though the systemic involvement is rare, it is life-threatening and represent a treatment challenge for the clinicians. We report a case of PWCD characterized by hepatic, hematologic, and renal involvement, with good response to mofetil mycophenolate and prednisone treatment. A 47-year-old female presented several months’ history of painful subcutaneous nodules, fever and lymphadenopathy with recent appearing of microcytic hypochromic anemia, leucopenia with neutropenia, and increase in transaminase. Skin biopsy showed lobular panniculitis with lymph-histiocytic and neutrophilic infiltrates with necrosis of adipocytes. A combination therapy of corticosteroid with mofetil mycophenolate was effective. Moreover, we discuss the clinical manifestation and the therapeutic choices in PWCD, from classical immunosuppressive drugs to new biotechnological agents, and we provide a comprehensive review of the available literature.

Multi-omics analysis of multiple missions to space reveal a theme of lipid dysregulation in mouse liver

Spaceflight has several detrimental effects on the physiology of astronauts, many of which are recapitulated in rodent models. Mouse studies performed on the Space Shuttle showed disruption of lipid metabolism in liver. However, given that these animals were not sacrificed on-orbit and instead returned live to earth, it is unclear if these disruptions were solely induced by space stressors (e.g. microgravity, space radiation) or in part explained by the stress of return to Earth. In this work we analyzed three liver datasets from two different strains of mice (C57BL/6 (Jackson) & BALB/c (Taconic)) flown aboard the International Space Station (ISS). Notably, these animals were sacrificed on-orbit and exposed to varying spaceflight durations (i.e. 21, 37, and 42 days vs 13 days for the Shuttle mice). Oil Red O (ORO) staining showed abnormal lipid accumulation in all space-flown mice compared to ground controls regardless of strain or exposure duration. Similarly, transcriptomic analysis by RNA-sequencing revealed several pathways that were affected in both strains related to increased lipid metabolism, fatty acid metabolism, lipid and fatty acid processing, lipid catabolic processing, and lipid localization. In addition, key upstream regulators were predicted to be commonly regulated across all conditions including Glucagon (GCG) and Insulin (INS). Moreover, quantitative proteomic analysis showed that a number of lipid related proteins were changed in the livers during spaceflight. Taken together, these data indicate that activation of lipotoxic pathways are the result of space stressors alone and this activation occurs in various genetic backgrounds during spaceflight exposures of weeks to months. If similar responses occur in humans, a prolonged change of these pathways may result in the development of liver disease and should be investigated further.

Metabolaid® Combination of Lemon Verbena and Hibiscus Flower Extract Prevents High-Fat Diet-Induced Obesity through AMP-Activated Protein Kinase Activation

Lemon verbena (Lippia citriodora) has been used as a food spice, cosmetic, and in traditional medicine formulations to treat asthma and diabetes in South America and Southern Europe. Hibiscus flower (Hibiscus sabdariffa L.) is used in traditional Chinese medicine in the form of a tea to treat hypertension and inflammation. In the present study, we examined the synergistic effects of a formula of Metabolaid^® (MetA), a combination of lemon verbena and hibiscus-flower extracts, on obesity and its complications in high-fat-diet (HFD)-induced obese mice. The results showed that MetA decreased body weight, white adipose tissue (WAT), and liver weight. Additionally, serum and hepatic lipid profiles, glucose levels, glucose tolerance, and cold-induced thermogenesis were significantly improved. Appetite-regulating hormones adiponectin and leptin were significantly increased and decreased, respectively, while the inflammatory-related factors tumor necrosis factor (TNF)-α and interleukin (IL)-6 were downregulated by MetA. Adipogenesis-activating gene expression was decreased, while increased thermogenesis-inducing genes were upregulated in the WAT, correlating with increased phosphorylation of AMPK and fatty-acid oxidation in the liver. Taken together, these results suggest that MetA decreased obesity and its complications in HFD mice. Therefore, this formula may be a candidate for the prevention and treatment of obesity and its complications.

Relationship between intestinal flora and inflammatory factors in patients with nonalcoholic steatohepatitis

This study was conducted to analyze the change in intestinal flora of patients with nonalcoholic steatohepatitis and its correlation to the levels of the inflammatory cytokines interleukin-10 (IL-10) and IL-17. We selected 90 patients that were diagnosed with and treated for nonalcoholic steatohepatitis as the patient group and 80 healthy cases as the control group. We then compared the intestinal flora in the subject feces and the intestinal colonization resistance (B/E, Bifidobacterium to Enterobacter) of both groups. Using RT-PCR, we also detected IL-10 and IL-17 mRNA levels in the peripheral blood mononuclear cells of both groups. Furthermore, we used the ELISA method to determine serum IL-10 and IL-17 levels in order to explore the correlation between IL-10, IL-17 and B/E. The number of Bifidobacterium and Lactobacillus were significantly lower in the patient group than the control group (P<0.05), while Enterobacter and Enterococcus pathogenic bacteria were significantly higher in the patient group than the control group (P<0.05). The B/E value was lower in the patient group than the control group (P<0.05). The relative expression of IL-10 and IL-17 mRNA in the patient group was significantly higher than in the control group (P<0.05). In the patient group, the serum IL-10 levels were 1.17±0.15 pg/ml, which is significantly higher than the control group serum IL-10 levels which were 0.32±0.04 pg/ml (P<0.05). The serum IL-17 levels in the patient groups were 0.96±0.11 pg/ml, which was significantly higher than the control group, which had an average of 0.28±0.01 pg/ml serum IL-17 levels (P<0.05). Pearson's correlation analysis showed that the change of B/E value of intestinal flora in the patients group were negatively correlated with serum IL-10 (r=−0.546, P<0.05), and negatively correlated with serum IL-17 (r=−0.535, P<0.05). Therefore, compared to healthy people, the expression of IL-10 and IL-17 in the peripheral blood of patients with non-alcoholic fatty liver is high. The changes in intestinal flora in patients with nonalcoholic steatohepatitis are closely related to the changes of serum IL-10 and IL-17 levels, and they are involved in the development of nonalcoholic steatohepatitis.

Antiobesity Efficacy of Quercetin-Rich Supplement on Diet-Induced Obese Rats: Effects on Body Composition, Serum Lipid Profile, and Gene Expression

The antiobesity effects of quercetin-rich supplement (QRS), which contain quercetin, lycopene, taurine, and litchi flower extract, on a high-fat diet (HFD)-induced obese rats were investigated. The rats that consume HFD with QRS (185 mg/kg rat) have significantly modulated the final body weights [490 ± 11 (HFD) → 441 ± 11 (HFD+QRS) g], total body fat [112.9 ± 4.5 (HFD) → 86.6 ± 5.7 (HFD+QRS) g], liver weights [14.8 ± 0.4 (HFD) → 12.6 ± 0.4 (HFD+QRS) g/rat], and the serum TG [102.5 ± 7.3 (HFD) → 90.7 ± 6.5 (HFD+QRS) mg/dL] to a level that resembled the regular diet-consumed rats (p < 0.05). The excretion of lipid in the faeces augmented in QRS groups as compared with the nonsupplemented HFD group [faecal total lipid: 62.43 ± 2.80 (HFD) → 73.15 ± 0.88 (HFD+QRS) mg/g dried faeces, p < 0.05]. In the histological analysis, quercetin-rich formulation supplemented groups presented a much less lipid accumulation and smaller size of adipocytes. Moreover, a decreased serum thiobarbituric acid reactive substances [1.55 ± 0.17 (HFD) → 0.78 ± 0.04 (HFD+QRS) nmol MDA eq/mL serum] increased levels of serum Trolox equivalent antioxidant capacity [3.89 ± 0.08 (HFD) → 6.46 ± 0.20 (HFD+QRS) μmol/mL serum], and more active hepatic antioxidant enzymes were observed in the supplemented groups (p < 0.05). The result of this work is a good demonstration of how a combination of bioactive compounds could work synergistically and become very effective in disease prevention.

Proteomic Analyses of Cysteine Redox in High-Fat-Fed and Fasted Mouse Livers: Implications for Liver Metabolic Homeostasis

Intensive oxidative stress occurs during high-fat-diet-induced hepatic fat deposition, suggesting a critical role for redox signaling in liver metabolism. Intriguingly, evidence shows that fasting could also result in redox-profile changes largely through reduced oxidant or increased antioxidant levels. However, a comprehensive landscape of redox-modified hepatic substrates is lacking, thereby hindering our understanding of liver metabolic homeostasis. We employed a proteomic approach combining iodoacetyl tandem mass tag and nanoliquid chromatography tandem mass spectrometry to quantitatively probe the effects of high-fat feeding and fasting on in vivo redox-based cysteine modifications. Compared with control groups, ∼60% of cysteine residues exhibited downregulated oxidation ratios by fasting, whereas ∼94% of these ratios were upregulated by high-fat feeding. Importantly, in fasted livers, proteins exhibiting diminished cysteine oxidation were annotated in pathways associated with fatty acid metabolism, carbohydrate metabolism, insulin, peroxisome proliferator-activated receptors, and oxidative respiratory chain signaling, suggesting that fasting-induced redox changes targeted major metabolic pathways and consequently resulted in hepatic lipid accumulation.

Combination of β-glucan and Morus alba L. Leaf Extract Promotes Metabolic Benefits in Mice Fed a High-Fat Diet

β-glucan (BG) and mulberry have received increasing attention for their benefits as natural sources of metabolic health. In the current study, we investigated the synergetic beneficial effects of BG and mulberry leaf extract (MLE) in mice fed a high-fat diet (HFD). Male C57BL6 mice were fed a HFD for twelve weeks to induce significant obesity and insulin resistance. BG and MLE were administrated orally throughout the feeding period. The administration of BG resulted in a significant reduction in body weight gain, perirenal fat mass, fasting insulin, serum lipids, serum inflammation markers, and fatty liver, showing systemic health improvement. Likewise, the administration of MLE showed benefits similar to BG, with the exception of body weight gain. In addition to the systemic benefits, the combination of BG and MLE resulted in a synergetic improvement in insulin sensitivity. Meanwhile, only the combination of BG and MLE significantly enhanced liver GST (Glutathione S-Transferase) activity and CuZn–SOD (Superoxide dismutase (Cu-Zn)) activity, resulting in a significant reduction in GSH/GSSG (Glutathione disulfide) and reactive oxygen species (ROS) levels in the liver. These results further confirm the beneficial effects of BG and MLE on metabolic disorders and show that the combination of BG and MLE has synergetic effects.

Monitoring the efficacy of omega-3 supplementation on liver steatosis and carotid intima-media thickness: a pilot study

Purpose

To determine the effects of omega‐3 supplementation on liver fat and carotid intima–media thickness (IMT) and to assess accuracy of ultrasound (US) for grading liver steatosis.

Materials and Methods

In this one‐way crossover pilot study, we assigned children with obesity and liver steatosis to receive 1.2 g daily of omega‐3 supplementation vs. inactive sunflower oil for 24 or 12 weeks. Liver fat content was assessed by magnetic resonance spectroscopy (MRS), magnetic resonance imaging (MRI) and US, and common carotid IMT by US. Statistical analysis included Chi‐square, Student's t‐tests, ANOVA tests and receiver operating characteristic (ROC) curves.

Results

Omega‐3 supplementation was associated with a trend towards decrease in MRS‐determined liver fat fraction (0.7% and 2.1% decrease in the 24‐week and 12‐week omega‐3 group, respectively) compared with the sunflower oil group (1.0% increase). These changes were not significant, whether assessed by MRS (P = 0.508), MRI (P = 0.508) or US (P = 0.678). Using US, the area under the ROC curves were 0.964, 0.817 and 0.783 for distinguishing inferred steatosis grades 0 vs. 1–2–3, 0–1 vs. 2–3 and 0–1–2 vs. 3, respectively, indicating good accuracy of US‐based fat grading. Omega‐3 supplementation was associated with a decrease in US‐determined IMT (0.05‐mm decrease in the 24‐week omega‐3 group. A 0.015‐mm increase was found in the 12‐week omega‐3 group, and a 0.007‐mm decrease in the sunflower oil group (P = 0.003).

Conclusion

Omega‐3 supplementation had no significant effect on liver fat fraction, but led to carotid IMT decrease in children with obesity and liver steatosis.

Obesity Leads to Tissue, but not Serum Vitamin A Deficiency

Obesity negatively affects multiple metabolic pathways, but little is known about the impact of obesity on vitamin A (VA)[retinol (ROL)], a nutrient that regulates expression of genes in numerous pathways essential for human development and health. We demonstrate that obese mice, generated from a high fat diet (HFD) or by genetic mutations (i.e., ob/ob; db/db), have greatly reduced ROL levels in multiple organs, including liver, lungs, pancreas, and kidneys, even though their diets have adequate VA. However, obese mice exhibit elevated serum VA. Organs from obese mice show impaired VA transcriptional signaling, including reductions in retinoic acid receptor (RARα, RARβ2 and RARγ) mRNAs and lower intracellular ROL binding protein Crbp1 (RBP1) levels in VA-storing stellate cells. Reductions in organ VA signaling in obese mice correlate with increasing adiposity and fatty liver (steatosis), while with weight loss VA levels and signaling normalize. Consistent with our findings in obese mice, we show that increasing severity of fatty liver disease in humans correlates with reductions in hepatic VA, VA transcriptional signaling, and Crbp1 levels in VA storing stellate cells. Thus, obesity causes a “silent” VA deficiency marked by reductions in VA levels and signaling in multiple organs, but not detected by serum VA.

Ontogeny of hepatic energy metabolism genes in mice as revealed by RNA-sequencing

The liver plays a central role in metabolic homeostasis by coordinating synthesis, storage, breakdown, and redistribution of nutrients. Hepatic energy metabolism is dynamically regulated throughout different life stages due to different demands for energy during growth and development. However, changes in gene expression patterns throughout ontogeny for factors important in hepatic energy metabolism are not well understood. We performed detailed transcript analysis of energy metabolism genes during various stages of liver development in mice. Livers from male C57BL/6J mice were collected at twelve ages, including perinatal and postnatal time points (n = 3/age). The mRNA was quantified by RNA-Sequencing, with transcript abundance estimated by Cufflinks. One thousand sixty energy metabolism genes were examined; 794 were above detection, of which 627 were significantly changed during at least one developmental age compared to adult liver. Two-way hierarchical clustering revealed three major clusters dependent on age: GD17.5–Day 5 (perinatal-enriched), Day 10–Day 20 (pre-weaning-enriched), and Day 25–Day 60 (adolescence/adulthood-enriched). Clustering analysis of cumulative mRNA expression values for individual pathways of energy metabolism revealed three patterns of enrichment: glycolysis, ketogenesis, and glycogenesis were all perinatally-enriched; glycogenolysis was the only pathway enriched during pre-weaning ages; whereas lipid droplet metabolism, cholesterol and bile acid metabolism, gluconeogenesis, and lipid metabolism were all enriched in adolescence/adulthood. This study reveals novel findings such as the divergent expression of the fatty acid β-oxidation enzymes Acyl-CoA oxidase 1 and Carnitine palmitoyltransferase 1a, indicating a switch from mitochondrial to peroxisomal β-oxidation after weaning; as well as the dynamic ontogeny of genes implicated in obesity such as Stearoyl-CoA desaturase 1 and Elongation of very long chain fatty acids-like 3. These data shed new light on the ontogeny of homeostatic regulation of hepatic energy metabolism, which could ultimately provide new therapeutic targets for metabolic diseases.

Pre-and-post transplant considerations in patients with nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is currently the third most common indication for liver transplantation in the United States. With the growing incidence of obesity, NAFLD is expected to become the most common indication for liver transplantation over the next few decades. As the number of patients who have undergone transplantation for NAFLD increases, unique challenges have emerged in the management and long-term outcomes in patients. Risk factors such as obesity, hypertension, diabetes, and hyperlipidemia continue to play an important role in the pathogenesis of the disease and its recurrence. Patients who undergo liver transplantation for NAFLD have similar long-term survival as patients who undergo liver transplantation for other indications. Research shows that post-transplantation recurrence of NAFLD is commonplace with some patients progressing to recurrent non-alcoholic steatohepatitis and cirrhosis. While treatment of comorbidities is important, there is no consensus on the management of modifiable risk factors or the role of pharmacotherapy and immunosuppression in patients who develop recurrent or de novo NAFLD post-transplant. This review provides an outline of NAFLD as indication for liver transplantation with a focus on the epidemiology, pathophysiology and risk factors associated with this disease. It also provides a brief review on the pre-transplant considerations and post-transplant factors including patient characteristics, role of obesity and metabolic syndrome, recurrence and de novo NAFLD, outcomes post-liver transplantation, choice of medications, and options for immunosuppression.

Effect of diet on expression of genes involved in lipid metabolism, oxidative stress, and inflammation in mouse liver-insights into mechanisms of hepatic steatosis

Nutritional intake is a fundamental determinant of health. Many studies have correlated excess caloric intake, as well as a high ratio of n-6:n-3 fatty acids, with detrimental health outcomes, such as the metabolic syndrome. In contrast, low-calorie diets have beneficial health effects. Despite these associations, our understanding of the causal relationship between diet and health remains largely elusive. The present study examined the molecular changes elicited by nine diets with varying fat, sugar, cholesterol, omega-3 fatty acids, omega-6 fatty acids, and calories in C57BL/6 male mice. Microarray analyses were conducted on liver samples from three mice per diet and detected 20,449 genes of which 3,734 were responsive to changes in dietary components. Principal component analysis showed that diet restriction correlated the least with the other diets and also affected more genes than any other diet. Interestingly, Gene Set Enrichment Analysis (GSEA) identified gene sets involved in glutathione metabolism, immune response, fatty acid metabolism, cholesterol metabolism, ABC transporters, and oxidative phosphorylation as being highly responsive to changes in diet composition. On the gene level, this study reveals novel findings such as the induction of the drug efflux pump Abcb1a (p-glycoprotein) by diet restriction and an atherogenic diet, as well as the suppression of the rate limiting step of bile acid synthesis, Cyp7a1, by a high fructose diet. This study provides considerable insight into the molecular changes incurred by a variety of diets and furthers our understanding of the causal relationships between diet and health.

Nonalcoholic fatty liver disease following liver transplantation

Post-transplant, nonalcoholic hepatic steatosis and steatohepatitis are increasingly recognized as a complication of liver transplantation, and the progression of the latter through fibrosis to cirrhosis has been clearly shown. Non-alcoholic steatohepatitis (NASH) is independently associated with an increased risk of death from cardiovascular and liver diseases. While optimal therapy is not yet available in the post-liver transplant setting, knowledge gained in the therapy of NASH in the non-transplant setting can be used to design therapeutic interventions. In addition, early recognition with protocol liver biopsies and an effective preventive strategy by modifying known risk factors implicated in the recurrence of NASH would be the most effective way to curtail the progression of NASH before an effective treatment can be found. Additional rigorous research aimed at elucidating the pathogenesis, natural history, and selection of immunosuppressants for NASH is clearly warranted.

Approach to Intraoperative Consultation for Donor Liver Biopsies

Context.— As demand for organs to treat end-stage liver disease increases, donor livers once deemed only marginally suitable for donation are being considered for transplantation. Pathologists are increasingly being asked to evaluate these livers for acceptability. This article provides guidelines for frozen section evaluation of livers for transplantation.

Objective.— This article concentrates on the histopathologic features of transplant suitability with appropriate clinicopathologic correlation for the practicing pathologist. Recommendations for proper handling and sampling of tissue are discussed. Relative and absolute contraindications as well as artifacts and benign conditions are emphasized.

Data Sources.— Sources include a compilation of the authors' experiences in academic and community liver transplantation centers. In addition, relevant medical literature was reviewed, as well as Web sites specializing in organ transplantation, such as Transplant Pathology Internet Services and the Organ Procurement and Transplantation Network.

Conclusions.— Malignancy and extensive necrosis in the liver are absolute contraindications to transplantation. Evaluation of macrosteatosis, fibrosis, hepatitis, and necrosis depends on the severity of disease and correlation with the clinical situation. Donor age of greater than 60 years does not preclude transplantation. Artifacts and benign conditions need to be understood to prevent wastage of precious organs and to ensure that an appropriate organ is provided for the recipient.

Effect of diabetes mellitus on pharmacokinetic and pharmacodynamic properties of drugs

The effects of diabetes mellitus on the pharmacokinetics and pharmacodynamics of drugs have been well described in experimental animal models; however, only minimal data exist for humans and the current knowledge regarding the effects of diabetes on these properties remains unclear. Nevertheless, it has been observed that the pharmacokinetics and pharmacodynamics of drugs are changed in subjects with diabetes. It has been reported that diabetes may affect the pharmacokinetics of various drugs by affecting (i) absorption, due to changes in subcutaneous adipose blood flow, muscle blood flow and gastric emptying; (ii) distribution, due to non-enzymatic glycation of albumin; (iii) biotransformation, due to regulation of enzymes/transporters involved in drug biotransformation; and (iv) excretion, due to nephropathy. Previously published data also suggest that diabetes-mediated changes in the pharmacokinetics of a particular drug cannot be translated to others. Although clinical studies exploring the effect of diabetes on pharmacodynamics are still very limited, there is evidence that disease-mediated effects are not limited only to pharmacokinetics but also alter pharmacodynamics. However, for many drugs it remains unclear whether these influences reflect diabetes-mediated changes in pharmacokinetics rather than pharmacodynamics. In addition, even though diabetes-mediated pharmacokinetics and pharmacodynamics might be anticipated, it is important to study the effect on each drug and not generalize from observed data. The available data indicate that there is a significant variability in drug response in diabetic subjects. The discrepancies between individual clinical studies as well as between ex vivo and clinical studies are probably due to (i) the restricted and focused population of subjects in clinical studies; (ii) failure to consider type, severity and duration of the disease; (iii) histopathological characteristics generally being missing; and (iv) other factors such as varying medication use, dietary protein intake, age, sex and obesity. The obesity epidemic in the developed world has also inadvertently influenced the directions of pharmacological research. This review attempts to map new information gained since Gwilt published his paper in Clinical Pharmacokinetics in 1991. Although a large body of research has been conducted and significant progress has been made, we still have to conclude that the available information regarding the effect of diabetes on pharmacokinetics and pharmacodynamics remains unclear and further clinical studies are required before we can understand the clinical significance of the effect. An understanding of diabetes-mediated changes as well as of the source of the variability should lead to the improvement of the medical management and clinical outcomes in patients with this widespread disease.

Comparative potential therapeutic effect of sesame oil and peanut oil against acute monocrotaline (Crotalaria) poisoning in a rat model

BACKGROUND

Many Crotalaria plant species contain hepatotoxic pyrrolizidine alkaloids (such as monocrotaline) that can cause acute and chronic poisoning in cattle and other animals.

HYPOTHESIS

Peanut oil, atropine sulfate, and antidiarrheal agents are used to treat acute monocrotaline poisoning. The effect of sesame on acute monocrotaline poisoning has never been investigated.

ANIMALS

Fifty male Sprague-Dawley rats were used for toxicity studies.

METHODS

Experiment 1: Group I, control. Groups II-IV were given monocrotaline (205.2 mg/kg) and euthanized 6, 12, and 24 hours later. Experiment 2: Group I, control. Group II monocrotaline alone (205.2 mg/kg). Groups III-VI were given monocrotaline (205.2 mg/kg) and 1 hour later, Groups III and IV were given sesame oil (1 and 2 mL/kg) and Groups V and VI were given peanut oil (1 and 2 mL/kg).

RESULTS

Monocrotaline significantly decreased (P < .05) serum amylase activity, but, over time, increased (P < .05) pancreatic and lung injury. AST and ALT activity and liver injury peaked at 24 hours. Sesame oil and peanut oil (P < .05) inhibited the changes in all tested parameters in acute monocrotaline poisoning. Although peanut oil inhibited acute monocrotaline poisoning, it induced steatosis, but sesame oil did not.

CONCLUSION AND CLINICAL IMPORTANCE

We hypothesize that early pancreatic and lung injury and late liver injury contribute to acute monocrotaline poisoning and that sesame oil is more efficacious than peanut oil against acute monocrotaline poisoning in rats. However, additional studies are needed to confirm that these oils have the same effects in cattle and other animals.

Selection of reference genes for qRT-PCR in high fat diet-induced hepatic steatosis mice model

With the epidemic proportions of obesity worldwide and the concurrent prevalence of hepatic steatosis, there is an urgent need for better understanding the intrinsic mechanism of hepatic steatosis, especially the changes of gene expression underlying the development of hepatic steatosis and its associated abnormal liver function. Quantitative real-time PCR (qRT-PCR) is a sensitive and highly reproducible technique of gene expression analysis. However, for accurate and reliable gene expression results, it is vital to have an internal control gene expressed at constant levels under all the experimental conditions being analyzed for. In this study, the authors validated candidate reference genes suitable for qRT-PCR profiling experiments using livers from control mice and high fat diet-induced obese mice. Cross-validation of expression stability of ten selected reference genes using three popular algorithms, GeNorm, NormFinder, and BestKeeper found HPRT1 and GAPDH as most stable reference genes. Thus, HPRT1 and GAPDH are recommended as stable reference genes most suitable for gene expression studies in the development of hepatic steatosis.

Endocrine disrupting chemicals and other substances of concern in food contact materials: an updated review of exposure, effect and risk assessment

Food contact materials (FCM) are an underestimated source of chemical food contaminants and a potentially relevant route of human exposure to endocrine disrupting chemicals (EDCs). Quantifying the exposure of the general population to substances from FCM relies on estimates of food consumption and leaching into food. Recent studies using polycarbonate plastics show that food simulants do not always predict worst-case leaching of bisphenol A, a common FCM substance. Also, exposure of children to FCM substances is not always realistically predicted using the common conventions and thus possibly misjudged. Further, the exposure of the whole population to substances leaching into dry foods is underestimated. Consumers are exposed to low levels of substances from FCM across their entire lives. Effects of these compounds currently are assessed with a focus on mutagenicity and genotoxicity. This approach however neglects integrating recent new toxicological findings, like endocrine disruption, mixture toxicity, and developmental toxicity. According to these new toxicology paradigms women of childbearing age and during pregnancy are a new sensitive population group requiring more attention. Furthermore, in overweight and obese persons a change in the metabolism of xenobiotics is observed, possibly implying that this group of consumers is insufficiently protected by current risk assessment practice. Innovations in FCM risk assessment should therefore include routine testing for EDCs and an assessment of the whole migrate toxicity of a food packaging, taking into account all sensitive population groups. In this article I focus on recent issues of interest concerning either exposure to or effects of FCM-related substances. Further, I review the use of benzophenones and organotins, two groups of known or suspected EDCs, in FCM authorized in the US and EU.

Phosphatidylcholine biosynthesis and lipoprotein metabolism

Phosphatidylcholine (PC) is the major phospholipid component of all plasma lipoprotein classes. PC is the only phospholipid which is currently known to be required for lipoprotein assembly and secretion. Impaired hepatic PC biosynthesis significantly reduces the levels of circulating very low density lipoproteins (VLDLs) and high density lipoproteins (HDLs). The reduction in plasma VLDLs is due in part to impaired hepatic secretion of VLDLs. Less PC within the hepatic secretory pathway results in nascent VLDL particles with reduced levels of PC. These particles are recognized as being defective and are degraded within the secretory system by an incompletely defined process that occurs in a post-endoplasmic reticulum compartment, consistent with degradation directed by the low-density lipoprotein receptor and/or autophagy. Moreover, VLDL particles are taken up more readily from the circulation when the PC content of the VLDLs is reduced, likely due to a preference of cell surface receptors and/or enzymes for lipoproteins that contain less PC. Impaired PC biosynthesis also reduces plasma HDLs by inhibiting hepatic HDL formation and by increasing HDL uptake from the circulation. These effects are mediated by elevated expression of ATP-binding cassette transporter A1 and hepatic scavenger receptor class B type 1, respectively. Hepatic PC availability has recently been linked to the progression of liver and heart disease. These findings demonstrate that hepatic PC biosynthesis can regulate the amount of circulating lipoproteins and suggest that hepatic PC biosynthesis may represent an important pharmaceutical target. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.

Berberine reducing insulin resistance by up-regulating IRS-2 mRNA expression in nonalcoholic fatty liver disease (NAFLD) rat liver

This study was performed to investigate the molecular mechanism and the therapeutic effect of berberine on nonalcoholic fatty liver disease (NAFLD). Rat models were given a high-fat diet (42% kcal) until they developed NAFLD, then were given normal saline (n=10), berberine (n-=10) at 187.5mg/kg/day, or pioglitazone (n=10) at 10.0mg/kg/day intragastrically for 4 weeks, respectively, and evaluated by hyperinsulinemic euglycemic clamping for insulin sensitivity. Serum biochemical markers and liver triglyceride (TG) were analyzed, real-time RT-PCR for mRNA expression and western blotting for protein expression of insulin receptor (IR) and insulin receptor substrate-2 (IRS-2) in liver tissues were performed, and hepatic histopathology in the rat models with NAFLD at the end of treatment was compared with normal controls (n=10). The NAFLD rats developed insulin resistance, showing increased fasting blood glucose and insulin levels, decreased glucose infusion rate, increased weight of epididymal fat (g/100g body weight), obvious hepatic steatosis and inflammation, and down-regulated IRS-2 mRNA and protein levels compared with normal controls (all P<0.05). In comparison with those treated with saline, model rats treated with berberine or pioglitazone underwent significant recovery, including up-regulated IRS-2 mRNA and protein (all P<0.05). Our results indicate that berberine may improve insulin resistance of NAFLD by up-regulating mRNA and protein levels of IRS-2, a key molecule in the insulin signaling pathway, suggesting that berberine may be used to treat NAFLD.

Nonalcoholic fatty liver disease across ethno-racial groups: do Asian-American adults represent a new at-risk population?

BACKGROUND AND AIM

Nonalcoholic fatty liver disease (NAFLD) is increasingly common worldwide. We explored clinical, laboratory, and histological features of NAFLD as well as risk factors for histologically advanced disease among under-represented ethno-racial groups.

METHODS

Patient records from one NAFLD clinic in California from 1998-2008 were reviewed. Biopsies were graded using Brunt criteria by a hepatopathologist blinded to clinical data. We used multivariate logistic regression to assess associations between ethno-racial group and histological severity of NAFLD, while controlling for other factors.

RESULTS

We identified 90 biopsy-proven cases of NAFLD. Mean age was 49 years (standard deviation [SD]= 11.6), and half were female. 52% of patients were Caucasian, 20% Latino-American, 18% Asian-American, and 10% Middle Eastern-American. There were significant differences among groups with respect to age, weight, body mass index (BMI), and grade of hepatic steatosis (all P < 0.05). In multivariate analysis, older age was associated with severe (Brunt ≥ 2) inflammation (odds ratio [OR] 1.1, P = 0.002) and severe (Brunt ≥ 3) fibrosis (OR 1.2, P = 0.001), diabetes was associated with severe inflammation (OR 3.18, P = 0.07) and severe fibrosis (OR 8.81, P = 0.002), and increased BMI was associated with severe fibrosis (OR 2.43, P = 0.07). Additionally, compared to Caucasians, Asian-Americans showed a trend toward an association with severe (Brunt > 2) steatosis (OR 3.83, P = 0.08) and severe inflammation (OR 5.42, P = 0.06).

CONCLUSIONS

The findings from this ethno-racially diverse clinic-based cohort are consistent with prior studies and also suggest that Asian-Americans may be at risk for advanced NAFLD. This may have implications for the prevention, evaluation, and treatment of patients with NAFLD that merit further study.

Identification of noninvasive biomarkers for alcohol-induced liver disease using urinary metabolomics and the Ppara-null mouse

Alcohol-induced liver disease (ALD) is a leading cause of nonaccident-related deaths in the United States. Although liver damage caused by ALD is reversible when discovered at the earlier stages, current risk assessment tools are relatively nonspecific. Identification of an early specific signature of ALD would aid in therapeutic intervention and recovery. In this study, the metabolic changes associated with ALD were examined using alcohol-fed male Ppara-null mouse as a model of ALD. Principal components analysis of the mass spectrometry-based urinary metabolic profile showed that alcohol-treated wild-type and Ppara-null mice could be distinguished from control animals without information on history of alcohol consumption. The urinary excretion of ethyl-sulfate, ethyl-beta-d-glucuronide, 4-hydroxyphenylacetic acid, and 4-hydroxyphenylacetic acid sulfate was elevated and that of the 2-hydroxyphenylacetic acid, adipic acid, and pimelic acid was depleted during alcohol treatment in both wild-type and the Ppara-null mice albeit to different extents. However, indole-3-lactic acid was exclusively elevated by alcohol exposure in Ppara-null mice. The elevation of indole-3-lactic acid is mechanistically related to the molecular events associated with development of ALD in alcohol-treated Ppara-null mice. This study demonstrated the ability of a metabolomics approach to identify early, noninvasive biomarkers of ALD pathogenesis in Ppara-null mouse model.

Qushi Huayu Decoction (祛湿化瘀方) inhibits protein and gene expression of cathepsin B in HepG2 cells induced by free fatty acids

OBJECTIVE

To study the experimental efficacy of Qushi Huayu Decoction (祛湿化瘀方,QHD) on, protein and gene expression of cathepsin B (ctsb) in HepG2 cells induced by free fatty acids (FFAs).

METHODS

The model of HepG2 steatosis and tumor necrosis factor-α (TNF-α) secretion was induced by long-chain FFAs. HepG2 cells were divided into 4 groups: control group (group C), model group (group M), low-dose QHD group (group L) and high-dose QHD group (group H). Long-chain FFAs were added to groups M, L and H. The 10% blank-control serum was added to group C and M, while 5% and 10% QHD-containing sera were added to group L and H, respectively. The levels of serum TNF-α and cellular triglyceride (TG) were detected. Cellular p-IκB and ctsb expression were detected using Western blot and PCR. The expression and distribution of ctsb were observed by immunofluorescence.

RESULTS

After incubating with FFA for 24 h, TG deposition in HepG2, TNF-α content in cell supernatant, the protein expression of cellular ctsb and P-IκB, as well as mRNA expression of ctsb increased markedly in group M compared with group C (P<0.05, P<0.01). Compared with group M, TG deposition, the expression of cellular ctsb, P-IκB and ctsb mRNA in groups L and H, as well as TNF-α content in group H, decreased significantly (P<0.05). Cell immunochemical fluorescence studies showed that ctsb was released from lysosomes and distributed in the cytoplasm extensively and diffusedly after being stimulated with FFA. In this study, these above-mentioned changes were inhibited markedly in groups L and H.

CONCLUSION

QHD might have a direct inhibitory effect on the ctsb target in the FFA-ctsb-TNFα pathway of hepatic lipotoxicity.

Interleukin-1beta may mediate insulin resistance in liver-derived cells in response to adipocyte inflammation

Central obesity is frequently associated with adipose tissue inflammation and hepatic insulin resistance. To identify potential individual mediators in this process, we used in vitro systems and assessed if insulin resistance in liver cells could be induced by secreted products from adipocytes preexposed to an inflammatory stimulus. Conditioned medium from 3T3-L1 adipocytes pretreated without (CM) or with TNFalpha (CM-TNFalpha) was used to treat Fao hepatoma cells. ELISAs were used to assess the concentration of several inflammatory mediators in CM-TNFalpha. CM-TNFalpha-treated Fao cells exhibited about 45% diminution in insulin-stimulated phosphorylation of insulin receptor, insulin receptor substrate proteins, protein kinase B, and glycogen synthase kinase-3 as compared with CM-treated cells, without changes in the total abundance of these protein. Insulin increased glycogenesis by 2-fold in CM-treated Fao cells but not in cells exposed to CM-TNFalpha. Expression of IL-1beta mRNA was elevated 3-fold in TNFalpha-treated adipocytes, and CM-TNFalpha had 10-fold higher concentrations of IL-1beta but not TNFalpha or IL-1alpha. IL-1beta directly induced insulin resistance in Fao, HepG2, and in primary rat hepatocytes. Moreover, when TNFalpha-induced secretion/production of IL-1beta from adipocytes was inhibited by the IL-1 converting enzyme (ICE-1) inhibitor II (Ac-YVAD-CMK), insulin resistance was prevented. Furthermore, liver-derived cells treated with IL-1 receptor antagonist were protected against insulin resistance induced by CM-TNFalpha. Finally, IL-1beta secretion from human omental fat explants correlated with body mass index (R(2) = 0.639, P < 0.01), and the resulting CM induced insulin resistance in HepG2 cells, inhibitable by IL-1 receptor antagonist. Our results suggest that adipocyte-derived IL-1beta may constitute a mediator in the perturbed cross talk between adipocytes and liver cells in response to adipose tissue inflammation.

Effect of obesity on the pharmacokinetics of drugs in humans

The prevalence of obesity has dramatically increased in recent years and now includes a significant proportion of the world's children, adolescents and adults. Obesity is linked to a number of co-morbidities, the most prominent being type 2 diabetes mellitus. While many agents are available to treat these conditions, the current knowledge regarding their disposition in the obese remains limited. Over the years, both direct and indirect methodologies have been utilized to assess body composition. Commonly used direct measures include underwater weighing, skinfold measurement, bioelectrical impedance analysis and dual-energy x-ray absorptiometry. Unfortunately, these methods are not readily available to the majority of clinicians. As a result, a number of indirect measures to assess body composition have been developed. Indirect measures rely on patient attributes such as height, bodyweight and sex. These size metrics are often utilized clinically and include body mass index (BMI), body surface area (BSA), ideal bodyweight (IBW), percent IBW, adjusted bodyweight, lean bodyweight (LBW) and predicted normal weight (PNWT). An understanding of how the volume of distribution (V(d)) of a drug changes in the obese is critical, as this parameter determines loading-dose selection. The V(d) of a drug is dependent upon its physiochemical properties, the degree of plasma protein binding and tissue blood flow. Obesity does not appear to have an impact on drug binding to albumin; however, data regarding alpha(1)-acid glycoprotein binding have been contradictory. A reduction in tissue blood flow and alterations in cardiac structure and function have been noted in obese individuals. At the present time, a universal size descriptor to describe the V(d) of all drugs in obese and lean individuals does not exist. Drug clearance (CL) is the primary determinant to consider when designing a maintenance dose regimen. CL is largely controlled by hepatic and renal physiology. In the obese, increases in cytochrome P450 2E1 activity and phase II conjugation activity have been observed. The effects of obesity on renal tubular secretion, tubular reabsorption, and glomerular filtration have not been fully elucidated. As with the V(d), a single, well validated size metric to characterize drug CL in the obese does not currently exist. Therefore, clinicians should apply a weight-normalized maintenance dose, using a size descriptor that corrects for differences in absolute CL between obese and non-obese individuals. The elimination half-life (t((1/2))) of a drug depends on both the V(d) and CL. Since the V(d) and CL are biologically independent entities, changes in the t((1/2)) of a drug in obese individuals can reflect changes in the V(d), the CL, or both. This review also examines recent publications that investigated the disposition of several classes of drugs in the obese--antibacterials, anticoagulants, antidiabetics, anticancer agents and neuromuscular blockers. In conclusion, pharmacokinetic data in obese patients do not exist for the majority of drugs. In situations where such information is available, clinicians should design treatment regimens that account for any significant differences in the CL and V(d) in the obese.

A role for Sp1 in transcriptional regulation of phosphatidylethanolamine N-methyltransferase in liver and 3T3-L1 adipocytes

Phosphatidylcholine is made in all nucleated mammalian cells via the CDP-choline pathway. Another major pathway for phosphatidylcholine biosynthesis in liver is catalyzed by phosphatidylethanolamine N-methyltransferase (PEMT). We have now identified 3T3-L1 adipocytes as a cell culture model that expresses PEMT endogenously. We have found that PEMT mRNA and protein levels increased dramatically in 3T3-L1 cells upon differentiation to adipocytes. 5'-Deletion analysis of the PEMT promoter-luciferase constructs stably expressed in 3T3-L1 adipocytes identified a regulatory region between -471 and -371 bp (relative to the transcriptional start site). Competitive and supershift assays demonstrated binding sites for transcription factors Sp1, Sp3 (-408 to -413), and YY1 (-417 to -420). During differentiation of 3T3-L1 cells to adipocytes, the amount of Sp1 protein decreased by approximately 50% just prior to activation of PEMT. Transduction of 3T3-L1 adipocytes with retrovirus containing Sp1 cDNA demonstrated that Sp1 inhibited PEMT transcriptional activity. Similarly, short hairpin RNA directed against Sp1 in 3T3-L1 adipocytes enhanced PEMT transcriptional activation. Chromatin immunoprecipitation assays confirmed that Sp1 binds to the PEMT promoter, and this interaction decreases upon differentiation to adipocytes. These experiments directly link increased PEMT expression in adipocytes to decreased transcriptional expression of Sp1. In addition, our data established that Sp1 binding was required for tamoxifen-mediated inhibition of Pemt promoter activity.

Dietary supplementation with branched-chain amino acids suppresses diethylnitrosamine-induced liver tumorigenesis in obese and diabetic C57BL/KsJ-db/db mice

Obesity and related metabolic abnormalities, including insulin resistance, are risk factors for hepatocellular carcinoma in non-alcoholic steatohepatitis as well as in chronic viral hepatitis. Branched-chain amino acids (BCAA), which improve insulin resistance, inhibited obesity-related colon carcinogenesis in a rodent model, and also reduced the incidence of hepatocellular carcinoma in obese patients with liver cirrhosis. In the present study, we determined the effects of BCAA on the development of diethylnitrosamine (DEN)-induced liver tumorigenesis in obese C57BL/KsJ-db/db (db/db) mice with diabetes mellitus. Male db/db mice were given tap water containing 40 ppm DEN for an initial 2 weeks and thereafter they received a basal diet containing 3.0% of BCAA or casein, which served as a nitrogen content-matched control of BCAA, throughout the experiment. Supplementation with BCAA significantly reduced the total number of foci of cellular alteration, a premalignant lesion of the liver, and the expression of insulin-like growth factor (IGF)-1, IGF-2, and IGF-1 receptor in the liver when compared to the casein supplementation. BCAA supplementation for 34 weeks also significantly inhibited both the development of hepatocellular neoplasms and the proliferation of hepatocytes in comparison to the basal diet or casein-fed groups. Supplementation with BCAA improved liver steatosis and fibrosis and inhibited the expression of alpha-smooth muscle actin in the DEN-treated db/db mice. The serum levels of glucose and leptin decreased by dietary BCAA, whereas the value of the quantitative insulin sensitivity check index increased by this agent, indicating the improvement of insulin resistance and hyperleptinemia. In conclusion, oral BCAA supplementation improves insulin resistance and prevents the development of liver tumorigenesis in obese and diabetic mice.

Quantification of lipid droplets and associated proteins in cellular models of obesity via high-content/high-throughput microscopy and automated image analysis

Intracellular lipid droplets are associated with a myriad of afflictions including obesity, fatty liver disease, coronary artery disease, and infectious diseases (eg, HCV and tuberculosis). To develop high-content analysis (HCA) techniques to analyze lipid droplets and associated proteins, primary human preadipocytes were plated in 96-well dishes in the presence of rosiglitazone (rosi), a PPAR-(c) agonist that promotes adipogenesis. The cells were then labeled for nuclei, lipid droplets, and proteins such as perilipin, protein kinase C (PKC), and hormone-sensitive lipase (HSL). The cells were imaged via automated digital microscopy and algorithms were developed to quantify lipid droplet (Lipid Droplet algorithm) and protein expression and colocalization (Colocalization algorithm). The algorithms, which were incorporated into Vala Science Inc's CyteSeer((R)) image cytometry program, quantified the rosi-induced increases in lipid droplet number, size, and intensity, and the expression of perilipin with exceptional consistency (Z' values of 0.54-0.71). Regarding colocalization with lipid droplets, Pearson's correlation coefficients of 0.38 (highly colocalized), 0.16 (moderate), and -0.0010 (random) were found for perilipin, PKC, and HSL, respectively. For hepatocytes (AML12, HuH-7, and primary cells), the algorithms also quantified the stimulatory and inhibitory effect of oleic acid and triacsin C on lipid droplets (Z's > 0.50) and ADFP expression/colocalization. Oleic acid-induced lipid droplets in HeLa cells and macrophages (THP-1) were also well quantified. The results suggest that HCA techniques can be utilized to quantify lipid droplets and associated proteins in many cell models relevant to a variety of diseases.

Psychometric analysis of the Three-Factor Eating Questionnaire-R21: results from a large diverse sample of obese and non-obese participants

BACKGROUND

The 21-item Three-Factor Eating Questionnaire (TFEQ-R21) is a scale that measures three domains of eating behavior: cognitive restraint (CR), uncontrolled eating (UE) and emotional eating (EE).

OBJECTIVES

To assess the factor structure and reliability of TFEQ-R21 (and if necessary, refine the structure) in diverse populations of obese and non-obese individuals.

DESIGN

Data were obtained from obese adults in a United States/Canadian clinical trial (n=1741), and overweight, obese and normal weight adults in a US web-based survey (n=1275). Confirmatory factor analyses were employed to investigate the structure of TFEQ-R21 using baseline data from the clinical trial. The model was refined to obtain adequate fit and internal consistency. The refined model was then tested using the web-based data. Relationships between TFEQ domains and body mass index (BMI) were examined in both populations.

RESULTS

Clinical data indicated that TFEQ-R21 needed refinement. Three items were removed from the CR domain, producing the revised version TFEQ-R18V2 (Comparative Fit Index (CFI)=0.91). Testing TFEQ-R18V2 in the web-based sample supported the revised structure (CFI=0.96; Cronbach's coefficient alpha of 0.78-0.94). Associations with BMI were small. In the clinical study, the CR domain showed a significant and negative association with BMI. On the basis of the web-based survey, it was shown that the relationship between BMI and CR is population-dependent (obese versus non-obese, healthy versus diabetics).

CONCLUSIONS

In two independent datasets, the TFEQ-R18V2 showed robust factor structure and good reliability. It may provide a useful tool for characterizing UE, CR and EE.

Effects of ovariectomy on PPAR alpha, SREBP-1c, and SCD-1 gene expression in the rat liver

OBJECTIVE

To investigate whether estrogen deficiency modifies the expression of important genes involved in hepatic lipid regulation, PPAR alpha, SREBP-1c, and SCD-1, in association with fat accumulation in the liver of ovariectomized rats.

DESIGN

Thirty female Sprague-Dawley rats were divided into three groups: sham-operated (n = 12), ovariectomized (n = 12), and ovariectomized with 17beta-estradiol replacement (n = 6). All animals were killed 8 weeks after surgery. In addition to liver triacylglycerol determination, transcripts levels and protein content of peroxisome proliferator-activated receptor alpha, liver sterol regulatory element-binding protein 1c, and stearoyl coenzyme Adesaturase 1 were quantified by quantitative real-time polymerase chain reaction and Western blot, respectively.

RESULTS

As expected, liver triacylglycerol levels were higher (51%; 21.9 +/- 2.6 vs 14.5 +/- 1.2 mg/g; P < 0.01) in ovariectomized compared with sham-operated rats. Peroxisome proliferator-activated receptor alpha mRNA levels were 66% lower (P < 0.01), whereas sterol regulatory element-binding protein 1 and stearoyl coenzyme A desaturase 1 transcript levels were 80% and 41% higher (P < 0.05), respectively, after estrogen removal. Our data on gene expression obtained with quantitative real-time polymerase chain reaction for peroxisome proliferator-activated receptor alpha and sterol regulatory element-binding protein 1c were confirmed by Western blots. All the effects of ovariectomy were prevented by 17beta-estradiol replacement, indicating a role for estrogens in the prevention of hepatic fat accumulation.

CONCLUSIONS

Our results suggest that a reduction in lipid oxidation and an increase in lipogenesis are defective mechanisms leading to lipid accumulation in the liver of ovariectomized rats. We conclude that estrogen deficiency induced by ovariectomy changes the expression of genes that favor the development of a steatotic phenotype.

Relationship between alanine aminotransferase levels and metabolic syndrome in nonalcoholic fatty liver disease

OBJECTIVE

To investigate the relationship between alanine aminotransferase (ALT) levels and metabolic syndrome (MS) in nonalcoholic fatty liver disease (NAFLD).

METHODS

A total of 26527 subjects who received medical health checkup in our hospital from January 2005 to July 2007 were enrolled in the study. The diagnosis of fatty liver was based on ultrasound imaging. MS was defined according to the criteria of the Adult Treatment Panel III. ALT, triglyceride (TG), high density lipoprotein cholesterol (HDL-c), fasting plasma glucose (FPG), height, weight, waist circumference (WC), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured in each subject to analyze the relationship between MS and ALT activity.

RESULTS

(1) The prevalence of NAFLD in men (30.94%) was significantly higher than that in women (15.65%); (2) The incidence of MS in NAFLD (33.83%) was significantly greater than that in non-NAFLD (10.62%); (3) Of the 6470 subjects with NAFLD, in the age-adjusted partial correlation analysis, there were statistically significant correlations between the ALT levels and most metabolic risk factors in each sex (P<0.01), except that ALT levels had no correlation with HDL-c in women. Moreover, in the multiple stepwise regression analysis, SBP lost its significance, and WC, body mass index (BMI), age, DBP, TG and FPG were independently associated with ALT levels in both sexes (P<0.05). HDL-c remained significant and was independently related to ALT levels in men; (4) ALT levels were significantly higher in subjects with MS compared to those without MS (P<0.001). Mean ALT levels increased with the number of MS components in each sex (P<0.05 for trend).

CONCLUSION

We found a strong relationship between ALT levels and MS in NAFLD and revealed that the cluster of MS components might be the predictor for ALT elevations.

Risk of venous thromboembolism in patients with liver disease: a nationwide population-based case-control study

OBJECTIVES

It is known that liver disease can cause an imbalance in the coagulation system, but available data on liver disease and risk of venous thromboembolism are conflicting. We examined the risk of venous thromboembolism in patients hospitalized with liver diseases.

METHODS

We conducted a nationwide Danish case-control study of incident cases of venous thromboembolism from 1980 to 2005 using population-based data from the National Registry of Patients, and from the Civil Registration System. We used conditional logistic regression to compute the relative risk of venous thromboembolism in patients with liver disease compared to population controls. We then excluded patients with known malignancy (diagnosed either before or up to 3 months after the venous thromboembolism) or fractures, trauma, surgery, or pregnancy within 90 days before the venous thromboembolism to estimate the risk associated with unprovoked venous thromboembolism.

RESULTS

A total of 99,444 patients with venous thromboembolism and 496,872 population controls were included in the study. Patients with liver disease had a clearly increased relative risk of venous thromboembolism, varying from 1.74 (95% CI, 1.54-1.95) for liver cirrhosis to 1.87 (95% CI, 1.73-2.03) for non-cirrhotic liver disease. The risks were higher for deep venous thrombosis compared with pulmonary embolism. In the analysis, restricted to 67,519 patients with unprovoked venous thromboembolism and 308,614 population controls, we found slightly higher relative risks: 2.06 (95% CI, 1.79-2.38) for liver cirrhosis and 2.10 (95% CI, 1.91-2.31) for non-cirrhotic liver disease.

CONCLUSIONS

Patients with liver disease have a substantially increased risk of venous thromboembolism.

Macaca radiata (bonnet monkey): a spontaneous model of nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a well-recognized condition that includes a spectrum of clinicopathology conditions ranging from steatotosis to cirrhosis and liver failure. Available animal models are not ideal as they show only a partial resemblance to characteristic human NAFLD.

OBJECTIVE

This study was aimed at identifying a nonhuman primate model of NAFLD resembling features of human NAFLD, which will be useful in understanding the mechanism of the onset of this disease and for developing novel therapeutic modalities.

METHODS

The histological status of the liver and serum levels of triglycerides (TG), cholesterol, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of aged bonnet monkeys were compared with that of the aged rhesus and adult bonnet monkeys. Histopathology and immunostaining of liver sections and oil red 'O' confirmed NAFLD in aged bonnet monkeys.

RESULTS

Aged bonnet monkeys showed a significant (P<0.01) increase in serum TG, AST and ALT compared with aged rhesus and adult bonnet monkeys. Histopathology of the liver of aged bonnet macaques showed diffused microvesicular and macrovesicular fatty changes, perivenular and portal and perisinusoidal fibrosis with fatty degeneration of hepatocytes, and immunostaining of liver sections was suggestive of NAFLD.

CONCLUSION

The spontaneous occurrence of NAFLD in normal animals is rare, but aged bonnet monkeys may serve as a unique animal model for studies related to NAFLD because they mimic pathophysiological features of human NAFLD.

Successive observation of laminin and hyaluronic acid on the formation of non-alcoholic fatty liver fibrosis in rabbits

AIM: To observe the changes of laminin (LN) and hyaluronic acid (HA) on the formation of non-alcoholic fatty liver fibrosis in rabbits.

METHODS: Firstly, the rabbit models of fatty liver and liver fibrosis were set up by hypercholesteremia. Liver tissues were collected and the histopathological changes were observed using transmission endoscopy and staining methods. Immunohistochemistry was used to detect LN expression and radioimmunoassy was used the measure serum HA concentration. Successive observation was used to outline the dynamic changes of basement membrane of hepatic sinusoid during the formation of non-alcoholic fatty liver fibrosis in rabbits.

RESULTS: Sinusoidal capillarization was characterized by defenestration of sinusoidal endothelial cells (SEC) and formation of basement membrane. Along with the formation of liver fibrosis, the positive expression (area percentage) of LN on sinusoidal wall and the concentration (mg/L) of serum HA increased gradually, and both of them reached the peak at 8 wk; there were significant differences in contrast with those in the normal group (LN: 25.2 ± 1.0 vs 5.1 ± 0.7, P < 0.01; serum HA: 1422.18 ± 20.9 vs 1189.3 ± 13.1, P < 0.01). After stopping high-sterone feeding, the positive expression of LN and concentration of HA decreased gradually.

CONCLUSION: The changes of serum HA concentration are in accordance with the defenestration of hepatic sinusoid and LN changes. LN and HA may be used as cardinal markers for hepatic sinusoidal capillarization and liver fibrosis.

Mitochondrial uncoupling protein-2 mediates steatotic liver injury following ischemia/reperfusion

Steatotic livers are not used for transplantation because they have a reduced tolerance for ischemic events with reduced ATP levels and greater levels of cellular necrosis, which ultimately result in total organ failure. Mitochondrial uncoupling protein-2 (UCP2) is highly expressed in steatotic livers and may be responsible for liver sensitivity to ischemia through mitochondrial and ATP regulation. To test this hypothesis, experiments were conducted in lean and steatotic (ob/ob), wild-type, and UCP2 knock-out mice subjected to total warm hepatic ischemi-a/reperfusion. Although ob/ob UCP2 knock-out mice and ob/ob mice have a similar initial phenotype, ob/ob UCP2 knock-out animal survival was 83% when compared with 30% in ob/ob mice 24 h after reperfusion. Serum alanine aminotransferase concentrations and hepatocellular necrosis were decreased in the ob/ob UCP2 knock-out mice when compared with ob/ob mice subjected to ischemia. Liver ATP levels were increased in the ob/ob UCP2 knock-out animals after reperfusion when compared with the ob/ob mice but remained below the concentrations from lean livers. Lipid peroxidation (thiobarbituric acid-reactive substances) increased after reperfusion most significantly in the steatotic groups, but the increase was not affected by UCP2 deficiency. These results reveal that UCP2 expression is a critical factor, which sensitizes steatotic livers to ischemic injury, regulating liver ATP levels after ischemia and reperfusion.