Investigation in our laboratory has been undertaken to study the effect of ethanol on the triglyceride (TG) content in the liver, the free fatty acid (FFA) content in the serum and the glycogen in the liver of rats which were fed on various diets. Four hours after administration of a sing1e dose of glucose (5g/kg BW.) and ethanol (6g/kg BW.) by gavage tube to rats fed a norma1 diet for 20 days then fasted for 18 hours, TG content in the liver increased by 80%, 10% compared to the control. When a sing1e dose of equal amounts of both glucose and ethanol were administered to another group, TG content in the liver was 42% higher than the control. There was no great change in serum FFA content in the glucose treated group as compared with the control, however, there was an increment of serum FFA content in the ethanol treated group and in the group treated with both ethanol and glucose by 81% and 71% of the control, respectively. The results indicate that ethanol administration had an inhibitory effect on the TG accumulation in the liver of rats fed by glucose. There is a correlation between TG accumulation in the liver and FFA content in the serum, and it appears that the ethanol administration did not induce the TG accumulation in the liver but the increment of serum FFA content in rats is probably due to the increased fatty acid mobilization from adipose tissue. However, countercurrent results were observed in the glucose treated group as compared with the ethanol treated group suggesting that glucose administration does induce TG accumulation in the liver but does not increase the serum FFA content in rats. The increment of serum FFA content in rats. The increment of serum FFA content by ethanol treatment was not ameliorated by glucose administration. In the liver perfusion experiment with rats fed both ethanol and various other diets, the results of incorporation of ethanol-1-14C into the total lipid in the high carbohydrate, high fat, low carbohydrate and control diet group were 1925 +/- 257 (cpm/g liver), 1237 +/- 76, 1269 +/- 105, 2041 +/- 74, respective1y. The results indicate that amount of dietary carbohydrate and high fat had an effect on the total lipid accumulation derived from ethanol-1-14C molecule in the liver. Liver glycogen content in the control on rats, high fat, 1ow carbohydrate and high carbohydrate diets were 91.5 +/- 7.9(mg%), 93.0 +/- 1.8, 99.1 +/- 4.4, and 153.7 +/- 26.0, respectively. There were no great differences between each dietary group and the rest control group except in the case of the high carbohydrate group which was over 1.5 times greater than that of the control. The incorporation of labelled ethanol into liver glycogen in the control rats and those on high fatdiet, low carbohydrate diet and high carbohydrate diet were 525, 401, 351 and 806 cpm/g liver, respectively. The increased incorporation of ethanol-1-14C into liver glycogen in the high carbohydrate diet group is thought to be due to the increased gluconeogenesis from acetyl CoA derived from 14C from ethanol because rats were fasted for 18 hours before perfusion. It might be the result of increased gluconegenesis of acetyl CoA derived from ethanol-1-14C by spare action of high carbohydrate on acetyl CoA. During the liver perfusion, 14CO2 production from ethanol-1-14C was higher in the high fat diet and low carbohydrate diet groups than in the control group, however, no great difference was observed between the high carbohydrate and control groups. The higher production of 14CO2 from the single ethanol-1-14C dose in rats on the high fat diet and low carbohydrate diet groups than in the control group is probably due to the increased metabolism of ethanol through Kreb's cycle rather than the incorporation of it into the liver fat.
Animal ; Diet ; Ethanol/metabolism ; Ethanol/pharmacology* ; Fatty Acids, Nonesterified/blood ; Glucose/pharmacology ; In Vitro ; Liver/metabolism* ; Male ; Rats ; Triglycerides/metabolism*

OBJECTIVETo review the current advances on the role of uncoupling protein (UCP) in the pathogenesis and progress of nonalcoholic fatty liver disease (NAFLD).

DATA SOURCESA comprehensive search of the PubMed literature without restriction on the publication date was carried out using keywords such as UCP and NAFLD.

STUDY SELECTIONArticles containing information related to NAFLD and UCP were selected and carefully analyzed.

RESULTSThe typical concepts, up-to-date findings, and existing controversies of UCP2 in NAFLD were summarized. Besides, the effect of a novel subtype of UCP (hepatocellular down regulated mitochondrial carrier protein, HDMCP) in NAFLD was also analyzed. Finally, the concept that any mitochondrial inner membrane carrier protein may have, more or less, the uncoupling ability was reinforced.

CONCLUSIONSConsidering the importance of NAFLD in clinics and UCP in energy metabolism, we believe that this review may raise research enthusiasm on the effect of UCP in NAFLD and provide a novel mechanism and therapeutic target for NAFLD.

Animals ; Fatty Acids, Nonesterified ; metabolism ; Fatty Liver ; etiology ; metabolism ; Humans ; Ion Channels ; physiology ; Mitochondrial Proteins ; analysis ; chemistry ; physiology ; Non-alcoholic Fatty Liver Disease ; Uncoupling Protein 2

OBJECTIVE: To investigate the changes of tetraspanin 8 (TSPAN8) expression levels and its role in lipid metabolism during the development of non-alcoholic fatty liver disease (NAFLD). METHODS: Thirty male C57BL/6J mice were randomly divided into normal diet group and high-fat diet (HFD) group (n=15), and after feeding for 1, 3, and 6 months, the expression levels of TSPAN8 in the liver tissues of the mice were detected with Western blotting. In a HepG2 cell model of NAFLD induced by free fatty acids (FFA), the effect of TSPAN8 overexpression on lipid accumulation was examined using Oil Red O staining and an automated biochemical analyzer, and the mRNA expressions of the key genes involved in lipid metabolism were detected using qRT-PCR. RESULTS: Western blotting showed that compared with that in mice with normal feeding, the expression of TSPAN8 was significantly decreased in the liver tissues of mice with HFD feeding for 3 and 6 months (P < 0.05). In HepG2 cells, treatment with FFA significantly decreased the expression of TSPAN8 at both the mRNA and protein levels (P < 0.01). TSPAN8 overexpression in FFA-treated cells showed significantly lowered intracellular triglyceride levels (P < 0.001) and obviously reduced mRNA expression of fatty acid transport protein 5 (FATP5) (P < 0.01). The expression of FATP5 was significantly increased in FFA-treated cells as compared with the control cells (P < 0.001). CONCLUSION TSPAN8 is involved in lipid metabolism in NAFLD, and overexpression of TSPAN8 may inhibit cellular lipid deposition by reducing the expression of FATP5.
Animals ; Diet, High-Fat/adverse effects* ; Fatty Acids, Nonesterified ; Lipid Metabolism ; Liver/metabolism* ; Male ; Mice ; Mice, Inbred C57BL ; Non-alcoholic Fatty Liver Disease/metabolism* ; RNA, Messenger/metabolism*

To investigate the effect of Huazhi Rougan Granules(HZRG) on autophagy in a steatotic hepatocyte model of free fatty acid(FFA)-induced nonalcoholic fatty liver disease(NAFLD) and explore the possible mechanism. FFA solution prepared by mixing palmitic acid(PA) and oleic acid(OA) at the ratio of 1∶2 was used to induce hepatic steatosis in L02 cells after 24 h treatment, and an in vitro NAFLD cell model was established. After termination of incubation, cell counting kit-8(CCK-8) assay was performed to detect the cell viability; Oil red O staining was employed to detect the intracellular lipid accumulation; enzyme-linked immunosorbnent assay(ELISA) was performed to measure the level of triglyceride(TG); to monitor autophagy in L02 cells, transmission electron microscopy(TEM) was used to observe the autophagosomes; LysoBrite Red was used to detect the pH change in lysosome; transfection with mRFP-GFP-LC3 adenovirus was conducted to observe the autophagic flux; Western blot was performed to determine the expression of autophagy marker LC3B-Ⅰ/LC3B-Ⅱ, autophagy substrate p62 and silent information regulator 1(SIRT1)/adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK) signaling pathway. NAFLD cell model was successfully induced by FFA at 0.2 mmol·L~(-1) PA and 0.4 mmol·L~(-1) OA. HZRG reduced the TG level(P<0.05, P<0.01) and the lipid accumulation of FFA-induced L02 cells, while elevated the number of autophagosomes and autophagolysosomes to generate autophagic flux. It also affected the functions of lysosomes by regulating their pH. Additionally, HZRG up-regulated the expression of LC3B-Ⅱ/LC3B-Ⅰ, SIRT1, p-AMPK and phospho-protein kinase A(p-PKA)(P<0.05, P<0.01), while down-regulated the expression of p62(P<0.01). Furthermore, 3-methyladenine(3-MA) or chloroquine(CQ) treatment obviously inhibited the above effects of HZRG. HZRG prevented FFA-induced steatosis in L02 cells, and its mechanism might be related to promoting autophagy and regulating SIRT1/AMPK signaling pathway.
Humans ; Non-alcoholic Fatty Liver Disease/metabolism* ; Sirtuin 1/metabolism* ; AMP-Activated Protein Kinases/metabolism* ; Fatty Acids, Nonesterified/metabolism* ; Autophagy ; Liver

Decreased glucose tolerance is often found in patients with thyrotoxicosis but the pathogenetic mechanisms are poorly understood. Since the concentrations of free fatty acid are usually elevated due to increased lipolysis in thyrotoxicosis, the preferential oxidation of the free fatty acids may explain the decreased glucose tolerance in hyperthyroidism. The aim of this study was to investigate whether lowering plasma free fatty acid(FFA) by acipimox, a long-acting antilipolytic agent, could affect glucose metabolism in thyrotoxicosis. We performed intravenous glucose tolerance test with acipimox or placebo in 6 untreated thyrotoxicmen and 6 age-and body mass index(BMI)-matched controls. The following results were obtained.1) The basal plasma FFA concentration in thyrotoxic patients were significantly higher than those in controls(997.0+-303.4 uEq/L vs. 290.5+-169.1 uEq/L; p<0.01). 2) Plasma FFA concentrations decreased rapidly with acipimox ingestion in both controls and thyrotoxic patients.3) Plasma glucose concentrations were significantly lower with acipimox ingestion than with placebo in thyrotoxic patients from 17min after intravenous glucose load and to the end of the study.4) Plasma insulin concentrations in thyrotoxic patients with acipimox ingestion were higher at 5, 7 min after iv glucose load.5) In thyrotoxic patients, glucose disappearance rate(K_glucose) in acipimox treatment was significantly higher than that in placebo treatment(2.44+-0.84 vs. 1.58+-0.37;p<0.05). 6) K_glucose values were inversely correlated with basal FFA concentrations(r=-0.58, p<0.05). In summary, in thyrotoxic patients with elevated plasma FFA levels, acipimox lowered plasma FFA, which in turn improved glucose tolerance.
Blood Glucose ; Eating ; Fatty Acids, Nonesterified ; Glucose ; Glucose Tolerance Test ; Humans ; Hyperthyroidism ; Insulin ; Lipolysis ; Metabolism ; Plasma ; Thyrotoxicosis

OBJECTIVETo investigate the effect of adiponectin on hepatocyte steatosis.

METHODSL02 cells were transfected with pEGFP-N1-AdipoQ, a plasmid encoding pEGFP-adiponectin fusion protein, or pEGFP-N1. Lipid droplets in the hepatocytes were observed by oil red staining at 72 h. The contents of TG, FFA and glycerol in hepatocytes were measured.

RESULTSCompared to cells transfected with pEGFP-N1-AdipoQ plasmid, much more lipid droplets were observed in cells transfected with pEGFP-N1 plasmid. TG, FFA and glycerol contents in L02 cells and L02/pEGFP-N1 cells were significantly higher than those in L02/pEGFP-N1-AdipoQ cells.

CONCLUSIONSOverexpression of adiponectin prevent hepatocyte steatosis.

Adiponectin ; genetics ; Cell Line ; Fatty Acids, Nonesterified ; analysis ; Fatty Liver ; metabolism ; Genetic Vectors ; Glycerol ; analysis ; Hepatocytes ; cytology ; metabolism ; Humans ; Plasmids ; Recombinant Fusion Proteins ; genetics ; Transfection ; Triglycerides ; analysis

The human intestinal microbiota is a community of 10(13)-10(14) microorganisms that harbor in the intestine and normally participate in a symbiotic relationship with human. Technical and conceptual advances have enabled rapid progress in characterizing the taxonomic composition, metabolic capacity and immunomodulatory activity of the human intestinal microbiota. Their collective genome, defined as microbiome, is estimated to contain > or =150 times as many genes as 2.85 billion base pair human genome. The intestinal microbiota and its microbiome form a diverse and complex ecological community that profoundly impact intestinal homeostasis and disease states. It is becoming increasingly evident that the large and complex bacterial population of the large intestine plays an important role in colorectal carcinogenesis. Numerous studies show that gut immunity and inflammation have impact on the development of colorectal cancer. Additionally, bacteria have been linked to colorectal cancer by the production of toxic and genotoxic bacterial metabolite. In this review, we discuss the multifactorial role of intestinal microbiota in colorectal cancer and role for probiotics in the prevention of colorectal cancer.
Animals ; Bacteroides/metabolism ; Colorectal Neoplasms/immunology/*microbiology ; Fatty Acids, Nonesterified/metabolism ; Humans ; Hydrogen Sulfide/metabolism ; Intestinal Mucosa/immunology/microbiology ; Metagenome ; *Probiotics ; Reactive Oxygen Species/metabolism ; Toxins, Biological/metabolism

Free fatty acid profiles of wild type and fatty acyl-ACP synthase deletion mutant strain of Synechocystis sp. PCC6803 indicated that one origin of these fatty acids is the process of lipid remodeling or lipid degradation. Lipase is the key enzyme involved in this process. The gene sll1969 is the sole gene encodes a putative lipase in Synechocystis sp. PCC6803. To identify the function of this gene and its role in fatty acid metabolism, we cloned the sll1969 from genomic DNA, overexpressed it in Escherichia coli BL21 (DE3) using pET expression system and purified this recombinant enzyme with Nickel-nitrilotriacetic acid affinity chromatography. The enzyme activity was assayed by spectrophotometric with p-nitro-phenylbutyrate as substrate. The K(m) and k(cat) of the enzyme is (1.16 +/- 0.01) mmol/L and (332.8 +/- 10.0)/min, respectively toward p-nitro-phenylbutyrate at 30 degrees C. The optimal temperature of the enzyme is 55 degrees C. To investigate the biological role of Sll1969 in fatty acid metabolism in cyanobacteria, we constructed sll1969 deletion and overexpression mutant strains in the background of fatty acyl-ACP synthase deletion mutant of Synechocystis sp. PCC6803. The analyses of the content of free fatty acids in different mutant strains showed that the contents of Sll1969 and free fatty acid are positively correlated. The free fatty acid profiles of the sll1969 mutant strains suggested this enzyme is not the sole enzyme for degrading lipid in Synechocystis sp. PCC6803.
Escherichia coli ; genetics ; metabolism ; Fatty Acids, Nonesterified ; metabolism ; Lipase ; biosynthesis ; genetics ; Membrane Lipids ; genetics ; metabolism ; Mutation ; Recombinant Proteins ; biosynthesis ; genetics ; metabolism ; Synechocystis ; enzymology ; genetics ; metabolism

OBJECTIVETo analyze the changes of patients with type 2 diabetes in different stages in glucagon (GC) and free fatty acid (FFA) in fasting, OGT and L-Arg experiments, and discusses the role of pancreatic alphabeta cells in diabetes pathogenesis by studying the relations among indexes such as glucagon (GC), free fatty acid (FFA) and blood glucose (BG), insulin, insulin homeostasis model (HOMA) and glucose metabolism hormone secretion curve, in order to provide theoretical basis for the treatment of diabetes.

METHODStudy objects were divided into the T2DM group (45 cases), the IGT group (28 cases) and the NGT group (30 cases) for an OGTT experiment and then an L-Arg experiment on the next day. Under the fasting state, their blood glucose (FBG), insulin (F), glucagon (FGC), free fatty acid (FFA) were detected to calculate HOMA-beta, insulin sensitivity index (ISI) and HOMA-IR of different groups. Meanwhile, efforts were made to calculate different time quantum detected in OGTT and L-Arg experiments and area under the curve AUC(BG), AUC(INS) and AUC(GC).

RESULTObvious overall differences were observed in FFA and FGC of the three groups. FGC of each group was negatively correlated with HOMA-beta and ISI. Among all of the 103 study objects, FGC was positively correlated with FBG and HOMA-IR and negatively correlated with HOMA-beta and ISI, with no correlation with FINS; FFA was positively correlated with FBG, HOMA-IR and negatively correlated with FINS, HOMA-beta, ISI. FGC and FFA were positively correlated in the T2DM group and the IGT group, but with no statistical correlation in the NGT group. The sequence of the three study objects was T2DM > IGR > NGT in AUC(GC) in the OGTT experiment and T2DM > IGR > NGT in in AUC(GC) in the L-Arg experiment, with the significant positive correlation between AUC(GC) and AUC(BG) and significant negative correlation with AUC(INS).

CONCLUSIONGlucagon and free fatty acid of T2DM and IGT patients increased, which was positively correlated with blood glucose and HOMA-IR and negatively correlated with INS, HOMA-beta and ISI. The increase in glucagons of T2DM and IGT patients indicated inappropriate secretion of pancreatic alphabeta cells among patients with type 2 diabetes.

Adult ; Blood Glucose ; metabolism ; Diabetes Mellitus, Type 2 ; metabolism ; Fatty Acids, Nonesterified ; metabolism ; Female ; Glucagon ; blood ; Humans ; Insulin ; secretion ; Islets of Langerhans ; secretion ; Male ; Middle Aged

Human carboxylesterase 1 (HCE1), belonging to a multigene serine hydrolase family, is a major liver carboxylesterase responsible for the hydrolysis and metabolism of various xenobiotics. It also plays an important role in the transportation and metabolism of endogenous cholesterol ester and free fatty acid, and is closely associated with the pathogenesis of hepatocellular carcinoma. This review describes current developments in the molecular structure, the roles in drug, toxins and lipid metabolism, and the early diagnosis for hepatocellular carcinoma of human carboxylesterase 1.
Carboxylic Ester Hydrolases ; genetics ; physiology ; Carcinoma, Hepatocellular ; diagnosis ; Cholesterol Esters ; metabolism ; Fatty Acids, Nonesterified ; metabolism ; Humans ; Liver Neoplasms ; diagnosis ; Xenobiotics ; metabolism