Metformin improves high-fat diet-induced insulin resistance in mice by downregulating the expression of long noncoding RNA NONMMUT031874.2.

Metformin (MET) is the first-line therapeutic option for patients with type 2 diabetes that has garnered substantial attention over recent years. However, an insufficient number of studies have been performed to assess its effects on insulin resistance and the expression profile of long noncoding RNAs (lncRNAs). The present study divided mice into three groups: Control group, high-fat diet (HFD) group and HFD + MET group. A high-throughput sequencing analysis was conducted to detect lncRNA and mRNA expression levels, and differentially expressed lncRNAs were selected. Subsequently, the differentially expressed lncRNAs were validated both in vivo and in vitro (mouse liver AML12 cells treated with Palmitic acid) models of insulin resistance. After validating randomly selected lncRNAs via reverse transcription-quantitative PCR a novel lncRNA, NONMMUT031874.2, was identified, which was upregulated in the HFD group and reversed with MET treatment. To investigate the downstream mechanism of NONMMUT031874.2, lncRNA-microRNA (miR/miRNA)-mRNA co-expression network was constructed and NONCODE, miRBase and TargetScan databases were used, which indicated that NONMMUT031874.2 may regulate suppressor of cytokine signaling 3 by miR-7054-5p. For the in vitro part of the present study, AML12 cells were transfected with small interfering RNA to knock down NONMMUT031874.2 expression before being treated with palmitic acid (PA) and MET. The results showed that the expression of NONMMUT031874.2 was significantly increased whereas miR-7054-5p expression was significantly decreased by PA treatment. By contrast, after knocking down NONMMUT031874.2 expression or treatment with MET, the aforementioned in vitro observations were reversed. In addition, it was also found that NONMMUT031874.2 knockdown and treatment with MET exerted similar effects in alleviating insulin resistance and whilst decreasing glucose concentration in AML12 cells. These results suggest that MET treatment can ameliorate insulin resistance by downregulating NONMMUT031874.2 expression.

ß-catenin mediates the effect of GLP-1 receptor agonist on ameliorating hepatic steatosis induced by high fructose diet.

The hypoglycemic drug GLP-1 receptor agonist can ameliorate hepatic steatosis but the mechanism is not clear. Intake of high fructose leads to non-alcoholic fatty liver disease by stimulating lipid synthesis, and ß-catenin is the key molecule for realizing GLP-1 function in extrahepatic tissues; with the discovery of GLP-1 receptor in liver, we speculate that ß-catenin might mediate GLP-1 receptor agonist on ameliorating hepatic steatosis induced by high fructose. Wistar rats were fed with high fructose diet for 8 weeks and then treated with GLP-1 receptor agonist exenatide for 4 weeks; the changes of lipid synthesis pathway factors, the expression and nuclear translocation of ß-catenin, and the hepatic steatosis of the rats were observed. After the intervention of exenatide, the hepatic steatosis induced by high fructose was improved, the nuclear translocation and expression of ß-catenin were facilitated, and the mRNA and protein expression of the upstream regulator SREBP-1 and the downstream key enzymes ACC, FAS and SCD-1 of de novo lipogenesis were down-regulated. GLP-1 receptor agonist may ameliorate hepatic steatosis induced by high fructose by ß-catenin regulating de novo lipogenesis pathway. GLP-1 receptor agonist may be a potential new drug for the treatment of non-alcoholic fatty liver disease, and the ß-catenin may be an important target for the drug therapy.

Prevalence of gastrointestinal parasites in free-range yaks (Bos grunniens) in Gansu Province, Northwest China.

BACKGROUND: Little information about the prevalence of gastrointestinal parasites in yaks (Bos grunniens) in northwest China is available. Therefore, the objective of the study was to quantify faecal egg counts of gastrointestinal parasites (helminths and coccidia) in free-range yaks from Gannan Tibetan Autonomous Prefecture, Gansu Province, Northwest China. RESULTS: Parasites were detected in 290 of 733 (39.56%) faecal samples. The results showed that Strongylidae, Trichuris spp. and Eimeria spp. were detected all year round, Strongyloides papillosus was detected in autumn and summer, and Nematodirus spp. was detected in both autumn and spring. In contrast, Fasciola spp. was only detected in spring. The prevalence rates of parasitic infections in different seasons were significantly different. CONCLUSIONS: To our knowledge, this is the first investigation of gastrointestinal parasites in yaks (Bos grunniens) in Gansu, China. The results demonstrated a high prevalence of gastrointestinal parasitic infections, specifically GN infections, in yaks in GTAP and these infections can cause economic losses to the local cattle industry.

Efficacy and Safety of Dulaglutide Versus Insulin Glargine in Chinese T2DM Patients: A Subgroup Analysis of a Randomized Trial (AWARD-CHN2).

INTRODUCTION: To evaluate efficacy and safety data of dulaglutide in Chinese patients with type 2 diabetes mellitus (T2DM) who had inadequate glycemic control with 1-2 oral antihyperglycemic medications (OAMs). METHODS: This is a subgroup analysis of a phase 3, open-label, randomized, parallel-arm, 52-week study in Chinese patients aged ≥ 18 years with T2DM who had inadequate glycemic control with OAMs (glycated hemoglobin [HbA1c] ≥ 7.0% and ≤ 11.0%). The primary endpoint was assessment of the noninferiority of dulaglutide 1.5 mg as measured by change in HbA1c, compared with insulin glargine (glargine), using a 0.4% noninferiority margin at week 26. RESULTS: A total of 607 patients from China were randomized 1:1:1 to once-weekly dulaglutide 1.5 or 0.75 mg or once-daily glargine. At week 26, the least squares mean (LSM) change from baseline in HbA1c was greater with dulaglutide 1.5 mg (- 1.67%) and dulaglutide 0.75 mg (- 1.31%) compared with glargine (- 1.11%). The LSM (95% confidence interval) for the difference of dulaglutide 1.5 mg and 0.75 mg vs glargine was - 0.56% (- 0.75 to - 0.37) and - 0.20% (- 0.39 to - 0.01), respectively. Both doses of dulaglutide were noninferior and superior to glargine at 26 weeks and 52 weeks (two-sided P value < 0.05). The mean body weight decreased (P < 0.001) and total hypoglycemia rates were lower (P < 0.05) in the dulaglutide groups compared with the glargine group. Gastrointestinal adverse events (AEs) were the most frequently reported AEs in dulaglutide groups. CONCLUSION: Both doses of dulaglutide are efficacious and tolerable in Chinese patients with T2DM who had inadequate glycemic control on OAMs. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT01648582. FUNDING: Eli Lilly and Company.

Polycystic Ovary Syndrome is Associated with Elevated Periostin Levels.

PURPOSE: Periostin is a secreted extracellular matrix protein that is strongly associated with triglyceride metabolism, chronic inflammation, and insulin resistance. Growing evidence suggests that there is a link between periostin and ovarian function. Our aim was to ascertain whether circulating periostin levels are altered in women with polycystic ovary syndrome (PCOS) and to further explore the relationship between periostin and glucose metabolism disorder in PCOS patients. METHODS: In total, 50 women with PCOS and 30 age-matched controls without PCOS were recruited for this cross-sectional study. Periostin levels were measured using ELISA as well. RESULTS: Circulating periostin levels were significantly elevated in PCOS women compared with controls [4206.75(222.00, 4815.25) vs. 430.75(142. 13, 730.86) ng/ml, P=0. 005]. Spearman's correlation analysis showed that serum periostin levels had a positive correlation with body mass index (BMI), uric acid, homeostasis model assessment of insulin resistance (HOMA-IR), high-sensitive C reactive protein (hs-CRP), and a negative correlation with insulin sensitivity index (ISI). Logistic regression models revealed that PCOS was correlated with waist to hip ratio (WHR), fasting blood glucose (FBG), and periostin levels. In addition, multivariate linear regression analyses showed that FBG, HOMA-IR, and the lipid accumulation index (LAP) were independent factors influencing serum periostin levels. CONCLUSION: PCOS is associated with elevated levels of periostin.

Role of X-Box Binding Protein-1 in Fructose-Induced De Novo Lipogenesis in HepG2 Cells.

BACKGROUND: A high consumption of fructose leads to hepatic steatosis. About 20-30% of triglycerides are synthesized via de novo lipogenesis. Some studies showed that endoplasmic reticulum stress (ERS) is involved in this process, while others showed that a lipotoxic environment directly influences ER homeostasis. Here, our aim was to investigate the causal relationship between ERS and fatty acid synthesis and the effect of X-box binding protein-1 (XBP-1), one marker of ERS, on hepatic lipid accumulation stimulated by high fructose. METHODS: HepG2 cells were incubated with different concentrations of fructose. Upstream regulators of de novo lipogenesis (i.e., carbohydrate response element-binding protein [ChREBP] and sterol regulatory element-binding protein 1c [SREBP-1c]) were measured by polymerase chain reaction and key lipogenic enzymes (acetyl-CoA carboxylase [ACC], fatty acid synthase [FAS], and stearoyl-CoA desaturase-1 [SCD-1]) by Western blotting. The same lipogenesis-associated factors were then evaluated after exposure of HepG2 cells to high fructose followed by the ERS inhibitor tauroursodeoxycholic acid (TUDCA) or the ERS inducer thapsigargin. Finally, the same lipogenesis-associated factors were evaluated in HepG2 cells after XBP-1 upregulation or downregulation through cell transfection. RESULTS: Exposure to high fructose increased triglyceride levels in a dose- and time-dependent manner and significantly increased mRNA levels of SREBP-1c and ChREBP and protein levels of FAS, ACC, and SCD-1, concomitant with XBP-1 conversion to an active spliced form. Lipogenesis-associated factors induced by high fructose were inhibited by TUDCA and induced by thapsigargin. Triglyceride level in XBP-1-deficient group decreased significantly compared with high-fructose group (4.41 ± 0.54 µmol/g vs. 6.52 ± 0.38 µmol/g, P < 0.001), as mRNA expressions of SREBP-1c (2.92 ± 0.46 vs. 5.08 ± 0.41, P < 0.01) and protein levels of FAS (0.53 ± 0.06 vs. 0.85 ± 0.05, P = 0.01), SCD-1 (0.65 ± 0.06 vs. 0.90 ± 0.04, P = 0.04), and ACC (0.38 ± 0.03 vs. 0.95 ± 0.06, P < 0.01) decreased. Conversely, levels of triglyceride (4.22 ± 0.54 µmol/g vs. 2.41 ± 0.35 µmol/g, P < 0.001), mRNA expression of SREBP-1c (2.70 ± 0.33 vs. 1.00 ± 0.00, P < 0.01), and protein expression of SCD-1 (0.93 ± 0.06 vs. 0.26 ± 0.05, P < 0.01), ACC (0.98 ± 0.09 vs. 0.43 ± 0.03, P < 0.01), and FAS (0.90 ± 0.33 vs. 0.71 ± 0.02, P = 0.04) in XBP-1s-upregulated group increased compared with the untransfected group. CONCLUSIONS: ERS is associated with de novo lipogenesis, and XBP-1 partially mediates high-fructose-induced lipid accumulation in HepG2 cells through augmentation of de novo lipogenesis.

MicroRNA-802 regulates hepatic insulin sensitivity and glucose metabolism.

The expression level of microRNA-802 (miR-802) is increased in livers of high-fat diet (HFD)-fed mice and obese human subjects; however, the function of miR-802 in the development of obesity-associated insulin resistance remains incompletely understood. Here we studied the potential role of miR-802 in regulating hepatic glucose metabolism and insulin sensitivity. Mice were fed either a standard chow diet or HFD for 12 weeks, and then the HFD mice were infected by injection with an adeno-associated virus expressing miR-802 or miR-802-SP. Six weeks after the injection, we measured blood glucose, plasma insulin, and insulin sensitivity in the mice. In addition, hepatic glucose levels and PI3K-Akt pathway gene expression were analyzed. Adeno-associated viral-mediated overexpression of miR-802 in the livers of HFD mice caused impaired glucose homeostasis and insulin sensitivity, thus giving rise to decreased protein level of pAkts473 and pPI3K, and increased protein levels of pPTEN, G6PC, and GluT2. In contrast, loss of miR-802 function in the liver of HFD mice led to increased pAkts473 and pPI3K, and decreased levels of pPTEN, G6PC, and GluT2, thereby improving glucose metabolism and insulin resistance. Our findings confirmed MiR-802 as a regulator of liver glucose metabolism and insulin signaling.

Impact of activating transcription factor 4 signaling on lipogenesis in HepG2 cells.

Non-alcoholic fatty liver disease (NAFLD) is a rapidly growing health threat that has previously been associated with lipogenesis. The direct effect of endoplasmic reticulum stress (ERS) inhibition on the induction of lipogenesis has not been investigated in hepatocytes in vitro. The impact of activating transcription factor­4 (ATF4) on the lipogenic pathway and hepatic insulin transduction in liver cells also requires further investigation. In the present study, the triglyceride (TG) content of HepG2 cells stimulated with fructose was investigated using a commercially available enzymatic assay, and the expression levels of lipogenesis­associated factors were determined by western blotting and reverse transcription­quantitative polymerase chain reaction. Notably, the TG content of HepG2 cells was increased following incubation with fructose, which was accompanied by ERS. 4­Phenylbutyric acid, an inhibitor of ERS, lowered the TG content by reducing the mRNA expression levels of sterol regulatory element­binding protein 1 (SREBP­1c) and carbohydrate­responsive element­binding protein (ChREBP), and the protein expression levels of fatty acid synthase (FAS), acetyl­CoA carboxylase (ACC) and stearoyl­CoA desaturase­1 (SCD­1). Conversely, tunicamycin, which is an inducer of ERS, increased the TG content and stimulated the expression of the above lipogeneic markers. ATF4 deficiency relieved TG accumulation and decreased the mRNA expression levels of SREBP­1c and ChREBP, and protein expression levels of FAS, ACC and SCD­1 in fructose­treated HepG2 cells. Conversely, ATF4 overexpression increased the TG content by upregulating the mRNA expression levels of SREBP­1c and ChREBP and protein expression levels of FAS, ACC and SCD­1. Inhibition of ERS was shown to protect HepG2 cells against fructose­induced TG accumulation, whereas induction of ERS stimulated hepatic lipogenesis. As a downstream transcription factor of the unfolded protein response, a deficiency in ATF4 attenuates fructose­induced lipogenesis; while an overexpression of ATF4 can induce TG accumulation through stimulating hepatic lipogenesis. The results of the present study suggested that ATF4 may exert various physiological roles in lipid metabolism depending on the nutrient composition. In addition, these results suggested that ATF4 has a role in regulating lipogenesis and in the development of NAFLD; thus ATF4 may be considered a therapeutic target for NAFLD.

Molecular characterization of Giardia duodenalis from white yaks in China.

Giardia duodenalis is one of the most common enteric parasites of humans and animals, including companion animals, livestock and wildlife. To date, the information about the prevalence and molecular characterization of G. duodenalis infection in white yaks was limited. In the present study, a total of 208 white yak fecal samples were collected from Tianzhu Tibetan Autonomous County (TTAC) between September 2013 and March 2014. Of the 208 white yak fecal samples, four samples (1.92%, all collected in March 2014) tested G. duodenalis-positive by PCR amplification of triosephosphate isomerase (tpi) gene. Sequence analysis confirmed the presence of G. duodenalis assemblage E. The present study revealed the presence and genotype of G. duodenalis in white yaks for the first time, and extended the host range of G. duodenalis. These results provided useful information for further genotyping or subtyping studies of G. duodenalis in white yaks.

Relationship between thioredoxin-interacting protein (TXNIP) and islet ß-cell dysfunction in patients with impaired glucose tolerance and hypertriglyceridemia.

AIMS: To study the relationship between thioredoxin-interacting protein (TXNIP) and pancreatic ß-cell function in patients with impaired glucose regulation and patients with both impaired glucose regulation and hypertriglyceridemia. METHODS: We analyzed a population of 90 patients with impaired glucose regulation (IGR), 87 patients with IGR and hypertriglyceridemia, and 90 subjects with normal glucose tolerance (NGT). The levels of plasma TXNIP, a regulator of cellular oxidative stress, were measured. The homeostasis model assessment for insulin resistance (HOMA-IR) was used to evaluate insulin resistance in all subjects. In addition, two factors (HOMA for ß-cell function [HOMA-ß]) and first-phase insulin response [FPIR]) were used to evaluate pancreatic ß-cell function. The correlations between the plasma levels of TXNIP, insulin resistance, and islet ß-cell dysfunction were analyzed using Pearson's correlation analysis. RESULTS: Compared with NGT, patients with IGR had significantly lower HOMA-ß and FPIR, and higher plasma levels of TXNIP. Compared with the IGR group, patients with both IGR and hypertriglyceridemia had significantly lower HOMA-ß and FPIR, and higher plasma levels of TXNIP. There was also a negative correlation between TXNIP and HOMA-ß or FPIR, and a positive correlation between TXNIP and HOMA-IR. CONCLUSIONS: These data showed that the level of TXNIP is increased in patients with IGR and patients with both IGR and hypertriglyceridemia, islet ß-cell dysfunction was related to the increased TXNIP in IGR patients.

Chinese medicine Jinlida (JLD) ameliorates high-fat-diet induced insulin resistance in rats by reducing lipid accumulation in skeletal muscle.

The present paper reports the effects of Jinlida (JLD), a traditional Chinese medicine which has been given as a treatment for high-fat-diet (HFD)-induced insulin resistance. A randomized controlled experiment was conducted to provide evidence in support of the affects of JLD on insulin resistance induced by HFD. The affect of JLD on blood glucose, lipid, insulin, adiponectin, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin (TBIL) in serum and lipid content in skeletal muscle was measured. Genes and proteins of the AMPK signaling pathway were analyzed by real time RT-PCR and Western blot. Adiponectin receptor 1 and 2 (ADIPOR1, ADIPOR2) and other genes involved in mitochondrial function and fat oxidation were analyzed by real time RT-PCR. Histological staining was also performed. JLD or pioglitazone administration ameliorated fasting plasma levels of glucose, insulin, triglyceride (TG), total cholesterol (TC), ALT, AST and non-esterified fatty acid (NEFA) (P < 0.05). Treatment with JLD or pioglitazone significantly reverted muscle lipid content (P < 0.05). JLD (1.5 g/kg) significantly increased plasma adiponectin concentration by 60.17% and increased AMPK and acetyl-CoA carboxylase (ACC) phosphorylation in skeletal muscle (P < 0.05). JLD administration increased levels of ADIPOR1 and ADIPOR2 by 1.48 and 1.29 respectively. Levels of genes involved in mitochondrial function and fat oxidation were increased. This study provides the molecular mechanism by which JLD ameliorates HFD-induced insulin resistance in rats.

[Expression of nesfatin-1/NUCB2 and ghrelin in gastric mucosa of rats with intrauterine growth retardation].

OBJECTIVE: To investigate the expression of nesfatin-1/NUCB2 and ghrelin in the gastric mucosa of rats with intrauterine growth retardation (IUGR) and its significance. METHODS: The IUGR animal model was established by feeding rats low-protein diets during their pregnancy. Newborn rats were divided into catch-up growth, non-catch-up growth and control groups. Protein and mRNA levels of nesfatin-1/NUCB2 and ghrelin in the gastric mucosa of rats were determined by RT-PCR and Western blot, respectively. RESULTS: Nesfatin-1/NUCB2 mRNA and protein were expressed in the gastric mucosa of rats immediately after birth, and their expression increased in an age-dependent manner in all three groups. Furthermore, the level of nesfatin-1/NUCB2 in the catch-up growth group was higher than that in the control group before weaning, whereas there was no significant difference in nesfatin-1/NUCB2 expression between the two groups after weaning. The level of nesfatin-1/NUCB2 in the non-catch-up growth group was lower than that in the catch-up growth group during the whole observation period. The level of ghrelin in the catch-up growth group was higher than that in the control group starting from day 12 after birth, whereas there was no significant difference in ghrelin expression between the two groups after weaning. The level of ghrelin in the non-catch-up growth group was lower compared with those in the catch-up growth and control groups from days 12 to 28 after birth. CONCLUSIONS: Nesfatin-1 and ghrelin are co-expressed in the gastric mucosa of rats with IUGR after birth and interact with each other to produce long-term nutritional regulation.

Associations between apolipoprotein CIII concentrations and microalbuminuria in type 2 diabetes.

Microalbuminuria (MAU) is a strong predictor of diabetic nephropathy (DN), which is the main cause of morbidity and mortality in patients with diabetes mellitus (DM). Dyslipidemia exists in the majority of patients with DM and contributes to micro- and macrovascular complications associated with DM. Apolipoprotein CIII (apoCIII) is an inhibitor of the activity of lipoprotein lipase, which metabolizes triglyceride (TG) in very low-density lipoprotein (VLDL) and facilitates its clearance from plasma. The aim of the present study was to investigate the associations between apoCIII and MAU and the effects of atorvastatin in type 2 diabetes. In total, 120 subjects were divided into type 2 diabetes and type 2 DN groups, while 60 healthy subjects were selected as controls. The patients with DN were administered 20 mg atorvastatin daily for 16 weeks. Blood pressure, body mass index (BMI) and levels of HbA1c, FBG, TG, VLDL-cholesterol (VLDL-C), apoCIII and MAU were markedly elevated in the type 2 diabetes and type 2 DN groups compared with those in the control group (P<0.01), while high-density lipoprotein-cholesterol (HDL-C) levels were decreased significantly (P<0.01). All patients with type 2 DN showed significantly elevated blood pressure, apoCIII levels, MAU, course of the disease and rate of stroke and retinopathy compared with the patients with type 2 diabetes (P<0.01). MAU was significantly positively correlated with the course of the disease, systolic blood pressure, diastolic blood pressure, BMI and HbA1c, FBG, TG, total cholesterol, low-density lipoprotein-cholesterol, VLDL-C and apoCIII levels (P<0.05), whereas negatively correlated with HDL-C levels (r=-0.194, P=0.020). Logistic regression analysis showed that apoCIII levels were independently associated with MAU (odds ratio, 1.100; 95% confidence interval, 1.037-1.153; P<0.001). Atorvastatin improved the lipid profile and MAU in patients with type 2 DN (P<0.01). Therefore, the present study demonstrated that an independent positive correlation exists between the levels of apoCIII and MAU in patients with type 2 diabetes. Furthermore, atorvastatin may be used to improve the lipid profile and MAU in type 2 DN.

The chemical chaperon 4-phenylbutyric acid ameliorates hepatic steatosis through inhibition of de novo lipogenesis in high-fructose-fed rats.

Non-alcoholic fatty liver disease caused by dietary factors such as a high fructose intake is a growing global concern. The aim of this study was to investigate the intervention effects of an endoplasmic reticulum stress (ERS) inhibitor 4-phenylbutyric acid (PBA) on liver steatosis induced by high-fructose feeding in rats and the possible underlying mechanisms. Wistar rats were divided into the control, high-fructose group (HFru) and PBA intervention (HFru-PBA) groups. PBA intervention was initiated following 4 weeks of high-fructose feeding. After 8 weeks of feeding, the ERS markers p-PERK, p-eIF2α, p-IRE-1, spliced XBP-1, ATF-6 were measured by western blotting. Liver triglyceride contents and morphological changes were examined. The protein expression of lipogenic key enzymes (ACC, FAS and SCD-1) and upstream transcriptional factors (SREBP-1c and ChREBP) were measured. The ERS-related cell events, oxidative stress and apoptosis, were evaluated by standard methods. Results demonstrated that PBA intervention significantly resolved hepatic ERS and improved liver steatosis induced by high-fructose feeding in rats. The protein expression of ACC, FAS, SCD-1 and SREBP-1c was upregulated in high-fructose-fed rats, whereas it decreased following PBA intervention. Oxidative stress and apoptosis were observed in livers of high-fructose-fed rats, but were alleviated by PBA intervention. ERS is involved in the development of fatty liver induced by a high fructose intake. ERS inhibition by PBA can therefore ameliorate liver steatosis through inhibition of hepatic lipogenesis.

Oxymatrine attenuates hepatic steatosis in non-alcoholic fatty liver disease rats fed with high fructose diet through inhibition of sterol regulatory element binding transcription factor 1 (Srebf1) and activation of peroxisome proliferator activated receptor alpha (Pparα).

The aim of this study was to examine the therapeutic effect of oxymatrine, a monomer isolated from the medicinal plant Sophora flavescens Ait, on the hepatic lipid metabolism in non-alcoholic fatty liver (NAFLD) rats and to explore the potential mechanism. Rats were fed with high fructose diet for 8 weeks to establish the NAFLD model, then were given oxymatrine treatment (40, 80, and 160 mg/kg, respectively) for another 8 weeks. Body weight gain, liver index, serum and liver lipids, and histopathological evaluation were measured. Enzymatic activity and gene expression of the key enzymes involved in the lipogenesis and fatty acid oxidation were assayed. The results showed that oxymatrine treatment reduced body weight gain, liver weight, liver index, dyslipidemia, and liver triglyceride level in a dose dependant manner. Importantly, the histopathological examination of liver confirmed that oxymatrine could decrease the liver lipid accumulation. The treatment also decreased the fatty acid synthase (FAS) enzymatic activity and increased the carnitine palmitoyltransferase 1A (CPT1A) enzymatic activity. Besides, oxymatrine treatment decreased the mRNA expression of sterol regulatory element binding transcription factor 1(Srebf1), fatty acid synthase (Fasn), and acetyl CoA carboxylase (Acc), and increased the mRNA expression of peroxisome proliferator activated receptor alpha (Pparα), carnitine palmitoyltransferase 1A (Cpt1a), and acyl CoA oxidase (Acox1) in high fructose diet induced NAFLD rats. These results suggested that the therapeutic effect of oxymatrine on the hepatic steatosis in high fructose diet induced fatty liver rats is partly due to down-regulating Srebf1 and up-regulating Pparα mediated metabolic pathways simultaneously.

Mitofusin-2 ameliorates high-fat diet-induced insulin resistance in liver of rats.

AIM: To investigate the effects of mitofusin-2 (MFN2) on insulin sensitivity and its potential targets in the liver of rats fed with a high-fat diet (HFD). METHODS: Rats were fed with a control or HFD for 4 or 8 wk, and were then infected with a control or an MFN2 expressing adenovirus once a week for 3 wk starting from the 9(th) wk. Blood glucose (BG), plasma insulin and insulin sensitivity of rats were determined at end of the 4(th) and 8(th) wk, and after treatment with different amounts of MFN2 expressing adenovirus (10(8), 10(9) or 10(10) vp/kg body weight). BG levels were measured by Accu-chek Active Meter. Plasma insulin levels were analyzed by using a Rat insulin enzyme-linked immunosorbent assay kit. Insulin resistance was evaluated by measuring the glucose infusion rate (GIR) using a hyperinsulinemic euglycemic clamp technique. The expression or phosphorylation levels of MFN2 and essential molecules in the insulin signaling pathway, such as insulin receptor (INSR), insulin receptor substrate 2 (IRS2), phosphoinositide-3-kinase (PI3K), protein kinase beta (AKT2) and glucose transporter type 2 (GLUT2) was assayed by quantitative real-time polymerase chain reaction and Western-blotting. RESULTS: After the end of 8 wk, the body weight of rats receiving the normal control diet (ND) and the HFD was not significantly different (P > 0.05). Compared with the ND group, GIR in the HFD group was significantly decreased (P < 0.01), while the levels of BG, triglycerides (TG), total cholesterol (TC) and insulin in the HFD group were significantly higher than those in the ND group (P < 0.05). Expression of MFN2 mRNA and protein in liver of rats was significantly down-regulated in the HFD group (P < 0.01) after 8 wk of HFD feeding. The expression of INSR, IRS2 and GLUT2 were down-regulated markedly (P < 0.01). Although there were no changes in PI3K-P85 and AKT2 expression, their phosphorylation levels were decreased significantly (P < 0.01). After intervention with MFN2 expressing adenovirus for 3 wk, the expression of MFN2 mRNA and protein levels were up-regulated (P < 0.01). There was no difference in body weight of rats between the groups. The levels of BG, TG, TC and insulin in rats were lower than those in the Ad group (P < 0.05), but GIR in rats infected with Ad-MFN2 was significantly increased (P < 0.01), compared with the Ad group. The expression of INSR, IRS2 and GLUT2 was increased, while phosphorylation levels of PI3K-P85 and AKT2 were increased (P < 0.01), compared with the Ad group. CONCLUSION: HFDs induce insulin resistance, and this can be reversed by MFN2 over-expression targeting the insulin signaling pathway.

Protective effects of matrine against progression of high-fructose diet-induced steatohepatitis by enhancing antioxidant and anti-inflammatory defences involving Nrf2 translocation.

The present study was aimed to investigate the hepatoprotective effects of matrine against nonalcoholic steatohepatitis induced by a high-fructose diet. After being fed a high-fructose diet (HFD) for 4weeks, male Wistar rats were orally administered matrine in three different doses (40, 80, or 160mg/kg) once daily. Serum and liver samples were collected after treatment with matrine for 4weeks. Lipid droplets within hepatocytes, infiltration of inflammatory cells, and necrotic foci in the liver were morphologically alleviated by matrine in a dose-dependent manner compared with the HFD group. ALT and AST in the blood and the triglyceride content in the liver also decreased. The increased malondialdehyde and depleted glutathione by HFD were ameliorated in a dose-related manner with matrine. Matrine promoted Nrf2 translocation to the nucleus with subsequently up-regulated antioxidative enzyme protein expression, and it enhanced antioxidant activities compared with the HFD group (p<0.05). The increased activity of nuclear factor-kappa B in the liver and the tumour necrosis factor-alpha levels in plasma induced by HFD were inhibited by matrine as well (p<0.05). In this study, we also found that matrine ameliorated HFD-induced hyperglycaemia and insulin resistance. Taken together, our findings demonstrate that matrine is effective in preventing conversion of high-fructose diet-induced hepatic steatosis into nonalcoholic steatohepatitis in rats.

[Progress in research of the mechanisms related with the hepatic steatosis in the nonalcoholic fatty liver disease].

With the increased morbidity of Nonalcoholic fatty liver disease, the pathogenesis of which has become one of the focuses for researchers. Many details need to be clarified. The hepatic steatosis has been taken as the clinical pathological characters and the "golden standard of diagnosis" for the nonalcoholic fatty liver disease. More and more studies have shown that the hepatic steatosis (mainly as triglycerides) is the consequence of hepatic lipid metabolism disequilibrium. Generally, the related metabolism pathways including lipid input, lipid uptake, de novo lipogenesis, fatty acid oxidation, fatty acid reesterification, and lipid secretion etc. In this review, we focused on the progress of some key enzymes involved in these pathways in order to clarify the possible molecular mechanisms and the effective targets so that to broad our vision about the prevention and treatment of non-alcoholic fatty liver disease.

Nesfatin-1 in newborns: relationship with endocrine and metabolic and anthropometric measures.

OBJECTIVE: To explore the relationship between nesfatin-1 and growth and development in newborns. METHODS: Blood samples for nesfatin-1, ghrelin, insulinlike growth factor-1 (IGF-1), insulin and glucose were obtained from preterm (n = 53) and term infants (n = 60), including appropriate for gestational age (AGA) (n = 32) and small for gestational age (SGA) infants (n = 28). The relationship between nesfatin-1 and other metabolic hormones or anthropometric parameters was evaluated. RESULTS: The concentrations of nesfatin-1, ghrelin and insulin and the homeostasis model assessment-insulin resistance index (HOMA-IR) were higher in SGA than AGA infants (p = 0.0358, 0.0163, 0.0001 and 0.0051, respectively), but IGF-1 levels and homeostasis model assessment-insulin sensitivity index (HOMA-ISI) were lower (p = 0.033 and 0.0001, respectively). Nesfatin-1 levels in SGA infants were higher on postnatal day 0 (PNDO) than in AGA infants (p = 0.0358) and lower on PND7 (p = 0.0002) and PND28 (p = 0.0488). A negative correlation showed between nesfatin-1 and oral calorie intake (r = -0.446; p = 0.017) and HOMA-ISI (r = -0.398; p = 0.036), and a positive correlation between nesfatin-1 and HOMA-IR (r = 0.43; p = 0.023) in SGA infants. CONCLUSION: Nesfatin-1 is involved in the physiological regulation of intrauterine and postnatal growth and development in SGA infants.

Similar changes in muscle lipid metabolism are induced by chronic high-fructose feeding and high-fat feeding in C57BL/J6 mice.

The aim of the present study was to investigate the effects of high fructose and high fat feeding on muscle lipid metabolism and to illustrate the mechanisms by which the two different dietary factors induce muscle lipid accumulation. C57BL/J6 mice were fed either a standard, high-fructose (HFru) or high-fat diet. After 16 weeks feeding, mice were killed and plasma triglyceride (TG) and free fatty acid (FFA) levels were detected. In addition, muscle TG and long chain acyl CoA (LCACoA) content was determined, glucose tolerance was evaluated and the protein content of fatty acid translocase CD36 (FATCD36) in muscle was measured. Mitochondrial oxidative function in the muscle was evaluated by estimating the activity of oxidative enzymes, namely cytochrome oxidase (COx), citrate synthase (CS) and ß-hydroxyacyl CoA dehydrogenase (ß-HAD), and the muscle protein content of carnitine palmitoyltransferase-1 (CPT-1), cyclo-oxygenase (COX)-1 and proliferator-activated receptor coactivator (PGC)-1α was determined. Finally, sterol regulatory element-binding protein-1c (SREBP-1c) gene expression and fatty acid synthase (FAS) protein content were determined in muscle tissues. After 16 weeks, plasma TG and FFA levels were significantly increased in both the HFru and HF groups. In addition, mice in both groups exhibited significant increases in muscle TG and LCACoA content. Compared with mice fed the standard diet (control group), those in the HFru and HF groups developed glucose intolerance and exhibited increased FATCD36 protein levels, enzyme activity related to fatty acid utilization in the mitochondria and protein expressions of CPT-1, COX-1 and PGC-1α in muscle tissue. Finally, mice in both the HFru and HF groups exhibited increase SREBP-1c expression and FAS protein content. In conclusion, high fructose and high fat feeding lead to similar changes in muscle lipid metabolism in C57BL/J6 mice. Lipid accumulation in the muscle may be associated with increased expression of proteins related to lipid transportation and synthesis.