In recent years, nonalcoholic fatty liver disease (NAFLD) has increased because of the growing prevalence of obesity and overweight in the pediatric population. It has become the most common form of chronic liver diseases in children and the related research on NAFLD is expanded. The "two-hit" and "multiple hit" hypothesis have been widely accepted, and some research has shown that genetic, diet structure and environmental factors appear to play a crucial role in the development of pediatric NAFLD. Though it is expected by researchers, there is not an available satisfactory noninvasive marker for the diagnosis of this disease. Fortunately, some new non-invasive prediction scores for pediatric NAFLD have been developed. There is currently no established special therapy, and lifestyle intervention should be adequate for most cases of NAFLD in children. This article reviews the advances in the current knowledge and ideas concerning pediatric NAFLD, and discusses the diagnosis, perspective therapies and scoring methods for this disease.
Child ; Humans ; Non-alcoholic Fatty Liver Disease ; diagnosis ; etiology ; genetics ; Polymorphism, Single Nucleotide ; Risk Factors

Nonalcoholic steatohepatitis (NASH) is characterized by hepatocyte injury and inflammatory cell infiltration, which has been linked to peripheral insulin resistance and increased levels of triglycerides in the liver. The purposes of this study were to establish a mouse model of NASH by feeding mice a 60% high-fat diet (HFD) and to demonstrate the anti-fibrotic effects of oleuropein, which has been shown to have anti-oxidant and anti-inflammatory properties, in this HFD-induced mouse model of NASH. C57BL/6 mice were divided into three groups: a regular diet group (Chow), a HFD group and an oleuropein-supplemented HFD group (OSD), which was fed a 0.05% OSD for 6 months. The effects of oleuropein in this model were evaluated using biochemical, histological and molecular markers. The expression levels of alpha-smooth muscle actin (alpha-SMA)and collagen type I in the HFD and OSD groups were evaluated using real-time PCR and western blotting. The body weight, biochemical marker levels, nonalcoholic fatty liver disease activity score, homeostasis model of assessment-insulin resistance (HOMA-IR) and leptin levels observed in the HFD group at 9 and 12 months were higher than those observed in the Chow group. The HOMA-IR and leptin levels in the OSD group were decreased compared with the HFD group. In addition, alpha-SMA and collagen type I expression were decreased by oleuropein treatment. We established a NASH model induced by HFD and demonstrated that this model exhibits the histopathological features of NASH progressing to fibrosis. Our results suggest that oleuropein may be pharmacologically useful in preventing the progression of steatohepatitis and fibrosis and may be a promising agent for the treatment of NASH in humans.
Actins/genetics/metabolism ; Animals ; Antihypertensive Agents/*therapeutic use ; Collagen Type I/genetics/metabolism ; Diet, High-Fat/*adverse effects ; Fatty Liver/*drug therapy/etiology/metabolism ; Fibrosis/etiology/metabolism/prevention & control ; Iridoids/*therapeutic use ; Leptin/genetics/metabolism ; Liver/metabolism/pathology ; Mice ; Mice, Inbred C57BL

Animals ; Fatty Liver ; etiology ; genetics ; Humans ; Non-alcoholic Fatty Liver Disease ; Risk Factors

Disease Progression ; Fatty Liver ; complications ; genetics ; pathology ; Genotype ; Hepatitis B, Chronic ; complications ; genetics ; pathology ; Hepatitis C, Chronic ; complications ; genetics ; pathology ; Humans ; Liver Cirrhosis ; etiology ; genetics ; pathology ; Polymorphism, Single Nucleotide

OBJECTIVETo study role of endoplasmic reticulum stress in the development of fatty liver fibrosis induced by methionine-choline-deficient diet in rats.

METHODSNon-alcoholic steatohepatitis was induced by 10 weeks- methionine-choline-deficient diet (MCDD), Markers of endoplasmic reticulum stress were determined by immunoblotting and real-time PCR.

RESULTSThe number of apoptotic hepatocytes, The expression levels of endoplasmic reticulum stress markers were increased significantly in MCDD group compared to control group (probability value less than 0.05 or probability value less than 0.01), while ratio of hepatocyte proliferation/apoptosis was decreased in MCDD group (probability value less than 0.01). The number of hepatocytes apoptosis, and the expression levels of endoplasmic reticulum stress markers were decreased significantly 2 weeks after the feeding with normal diet in MCDD group (probability value less than 0.05 or probability value less than 0.01).

CONCLUSIONMCDD induces endoplasmic reticulum stress and fibrosis in rats.

Animals ; Apoptosis ; Caspases ; genetics ; metabolism ; Cell Proliferation ; Choline ; administration & dosage ; metabolism ; Choline Deficiency ; Diet ; Disease Models, Animal ; Endoplasmic Reticulum ; physiology ; Fatty Liver ; complications ; Liver ; metabolism ; pathology ; Liver Cirrhosis ; diet therapy ; etiology ; physiopathology ; Male ; Methionine ; deficiency ; RNA, Messenger ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Wistar

BACKGROUNDCurrently it is unclear whether lipid accumulation occurs in a particular sequence and its relationship with whole body insulin resistance (IR). This study aimed to answer this question.

METHODSMale Sprague-Dawley (SD) rats were fed on a normal or a high-fat diet for 20 weeks. Serum triglycerides (TG), serum free fatty acids (FFA), fasting plasma glucose (FPG), and liver and skeletal muscle TG were measured. The glucose infusion rate (GIR) and mRNA levels of acetyl-CoA carboxylase (ACC) and carnitine palmitoyltransferase-1 (CPT-1) in the liver and skeletal muscle were determined at different stages.

RESULTSCompared with rats fed on the normal diet, serum FFA was not significantly increased in rats fed on the high-fat diet until 20 weeks. In contrast, liver TG was significantly increased by the high-fat diet by four weeks (20-fold; P < 0.01), and remained elevated until the end of the study. However, skeletal muscle TG was not significantly increased by the high-fat diet until 20 weeks (10.6-fold; P < 0.01), and neither was the FPG. The GIR was significantly reduced (1.6-fold; P < 0.01) by the high-fat diet after 8 weeks. The mRNA levels of ACC gradually increased over time and CPT-1 decreased over time, in both the liver and skeletal muscle in rats fed the high-fat diet.

CONCLUSIONSLipid accumulation in the liver occurs earlier than lipid accumulation in the skeletal muscle. Fatty liver may be one of the early markers of whole body IR. Changes in the gene expression levels of ACC and CPT-1 may have important roles in the process of IR development.

Acetyl-CoA Carboxylase ; genetics ; Animals ; Blood Glucose ; analysis ; Carnitine O-Palmitoyltransferase ; genetics ; Fatty Acids, Nonesterified ; blood ; Fatty Liver ; etiology ; Insulin Resistance ; Lipid Metabolism ; Liver ; metabolism ; Male ; Muscle, Skeletal ; metabolism ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Triglycerides ; metabolism

Animals ; Cholesterol ; blood ; Fatty Liver ; epidemiology ; etiology ; virology ; Genotype ; Hepacivirus ; genetics ; Hepatitis B ; blood ; complications ; virology ; Hepatitis C ; blood ; complications ; virology ; Humans ; Insulin Resistance ; Metabolic Syndrome ; etiology ; Mice ; Risk Factors ; Triglycerides ; blood

OBJECTIVETo study the role of S6K1 in the induction of SREBP1c in mouse hepatic cell by high glucose stimulation.

METHODSS6K1 shRNA recombinant adenovirus (S6K1Ax) was injected into tail vein of db/db mice and then hepatic triglycerol content was analyzed. Liver specimen were stained with HE. After transfection with S6K1Ax or pU6Ax, mouse hepatic AML12 cells were treated with high glucose, insulin or glucose and insulin, the expression of mSREBP1c was detected by RT-PCR. S6K1 protein was detected by Western blot.

RESULTSHepatic S6K1 protein in db/db mice was inhibited a week after S6K1Ax injection. Compared with the control group, hepatic triglycerol content of S6K1Ax group was decreased (0.65+/-0.02) mmol/L vs (0.56+/-0.01) mmol/L (t = 4.312, P less than 0.01), hepatocyte fat droplet and vaculor generation were also decreased, fatty liver was improved. The mSREBP1c expression in S6K1Ax transfected cells was lower than that in the control cells (0.03+/-0.01 vs 0.06+/-0.01, t = 5.624, P less than 0.01). Compared with the basal state, SREBP1c expression of both groups was increased on the insulin stimulation, S6K1Ax group was 0.06+/-0.02 (t = 8.452, P less than 0.01) and control group was 0.08+/-0.02 (t = 3.591, P less than 0.05). There is no difference between control and S6K1Ax group by glucose addition (P more than 0.05).

CONCLUSIONS6K1 acts on fatty synthesis by regulating mSREBP1c expression.

Adenoviridae ; genetics ; Animals ; Cell Line ; Fatty Acid Synthases ; genetics ; metabolism ; Gene Expression Regulation ; Glucose ; administration & dosage ; Insulin ; administration & dosage ; Liver ; metabolism ; pathology ; Liver Cirrhosis ; etiology ; metabolism ; pathology ; Mice ; Mice, Inbred Strains ; RNA Interference ; RNA, Messenger ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Ribosomal Protein S6 Kinases, 90-kDa ; genetics ; metabolism ; Staining and Labeling ; Sterol Regulatory Element Binding Protein 1 ; genetics ; metabolism ; Transfection ; Triglycerides ; metabolism

OBJECTIVETo investigate the role and molecular mechanism of resistin in inflammation of hepatocytes in nonalcoholic steatohepatitis.

METHODSRat models of NASH were established successfully. The expression of resistin mRNA and protein were examined by quantitative RT-PCR and immunohistolostaining, respectively. The murine hepatocytes AML-12 were incubated with recombinant resistin or LPS for 48 hours, and the concentration of TNF alpha, IL-6 in supernatant of AML-12 cells were quantified by enzyme linked immunosorbent assay (ELISA), the nuclear translocation NF- kappa B were observed by immunofluorescence.

RESULTSThe steatosis of hepatocytes, inflammation in the lobule and perisinusoidal fibrosis in livers were found, and the expression of resistin mRNA and protein were increased in livers of rat model of NASH. The expression of resistin mRNA was 2.5 and 4 time higher in 12 weeks and 16 weeks of rat models respectively than that in normal control. The positive staining of resistin protein can be found mainly around the central veins. The concentration of TNF alpha and IL-6 were (1.856 +/- 0.049) pg/ml and (9.463 +/- 1.216) pg/ml in supernantant of AML-12 cells 48 hours after recombinant resistin treatment, and (1.791 +/- 0.046) pg/ml, (8.738 +/- 1.101) pg/ml 48 hours after LPS treatment. There was no significant difference between them, but both were higher than that in normal control (P < 0.01). The NF- kappa B p65 nuclear translocation had been observed in AML-12 cells 3 hours after resistin or LPS treatment.

CONCLUSIONSResistin can induce the production of TNF alpha, IL-6 and other inflammatory factors by hepatocytes, and therefore is an important inflammatory factor in NASH.

Animals ; Cells, Cultured ; Disease Models, Animal ; Fatty Liver ; etiology ; metabolism ; Immunohistochemistry ; Inflammation ; etiology ; metabolism ; Inflammation Mediators ; metabolism ; Interleukin-6 ; metabolism ; Lipopolysaccharides ; pharmacology ; Liver ; drug effects ; metabolism ; pathology ; Male ; Mice ; NF-kappa B ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Wistar ; Resistin ; genetics ; metabolism ; pharmacology ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo explore liver X receptor alpha (LXR alpha) gene changes and their significance in nonalcoholic fatty liver disease (NAFLD) in rats.

METHODSA rat model of nonalcoholic fatty liver disease was produced with a fatty diet regime (feeding group, FG). Rats fed with normal diet served as controls (CG). The mRNA and protein expressions of LXR alpha in liver tissues were detected by reverse transcription and polymerase chain reaction (RT-PCR) and Western blot.

RESULTSThe concentration of free fatty acid (FFA) in the sera of GF rats started to increase to 0.33 mmol/L after 4 weeks of fat diet feeding, while the FFA of the CG was just 0.24+/-0.03 mmol/L, and the difference was significant (P<0.05). The concentration of ALT and AST in sera of the FG rats started to increase to 75.8 U/L and 138.9 U/L at the 8th week, much higher than those of the CG (P<0.01), and at the 12th week they increased further (P<0.01). Meanwhile, the mRNA and protein expressions of LXR alpha at the 2nd week was significantly increased to 0.62 (P>0.01) and its peak was reached at the 12th week (P<0.01). There was a significant positive correlation between the expression of LXR alpha and the degree of NAFLD.

CONCLUSIONThe changes of LXR alpha gene are closely related to the development of nonalcoholic fatty liver disease.

Animals ; Fatty Liver ; etiology ; metabolism ; pathology ; Gene Expression ; Liver ; metabolism ; pathology ; Liver X Receptors ; Male ; Orphan Nuclear Receptors ; genetics ; metabolism ; Rats ; Rats, Wistar