Catabolism In Liver Research Articles

Intestinal peroxisome proliferator-activated receptor α-fatty acid-binding protein 1 axis modulates nonalcoholic steatohepatitis.

Peroxisome proliferator-activated receptor α (PPARα) regulates fatty acid transport and catabolism in liver. However, the role of intestinal PPARα in lipid homeostasis is largely unknown. Here, intestinal PPARα was examined for its modulation of obesity and NASH. Intestinal PPARα was activated and fatty acid-binding protein 1 (FABP1) up-regulated in humans with obesity and high-fat diet (HFD)-fed mice as revealed by using human intestine specimens or HFD/high-fat, high-cholesterol, and high-fructose diet (HFCFD)-fed C57BL/6N mice and PPARA -humanized, peroxisome proliferator response element-luciferase mice. Intestine-specific Ppara or Fabp1 disruption in mice fed a HFD or HFCFD decreased obesity-associated metabolic disorders and NASH. Molecular analyses by luciferase reporter assays and chromatin immunoprecipitation assays in combination with fatty acid uptake assays in primary intestinal organoids revealed that intestinal PPARα induced the expression of FABP1 that in turn mediated the effects of intestinal PPARα in modulating fatty acid uptake. The PPARα antagonist GW6471 improved obesity and NASH, dependent on intestinal PPARα or FABP1. Double-knockout ( Ppara/Fabp1ΔIE ) mice demonstrated that intestinal Ppara disruption failed to further decrease obesity and NASH in the absence of intestinal FABP1. Translationally, GW6471 reduced human PPARA-driven intestinal fatty acid uptake and improved obesity-related metabolic dysfunctions in PPARA -humanized, but not Ppara -null, mice. Intestinal PPARα signaling promotes NASH progression through regulating dietary fatty acid uptake through modulation of FABP1, which provides a compelling therapeutic target for NASH treatment.

Mouse Model of Weak Depression Exhibiting Suppressed cAMP Signaling in the Amygdala, Lower Lipid Catabolism in Liver, and Correlated Gut Microbiota

To establish a mouse model of weak depression, we raised 6-week-old C57BL/6N mice in single (SH) or group housing (GH) conditions for 2 weeks. The SH group showed less social interaction with stranger mice, learning disability in behavioral tests, and lower plasma corticosterone levels. The cecal microbiota of the SH group showed significant segregation from the GH group in the principal coordinate analysis (PCoA). Transcriptome analysis of the amygdala and liver detected multiple differentially expressed genes (DEGs). In the amygdala of SH mice, suppression of the cyclic adenine monophosphate (cAMP) signal was predicted and confirmed by the reduced immunoreactivity of phosphorylated cAMP-responsive element-binding protein. In the liver of SH mice, downregulation of beta-oxidation was predicted. Interestingly, the expression levels of over 100 DEGs showed a significant correlation with the occupancy of two bacterial genera, Lactobacillus (Lactobacillaceae) and Anaerostipes (Lachnospiraceae). These bacteria-correlated DEGs included JunB, the downstream component of cAMP signaling in the amygdala, and carnitine palmitoyltransferase 1A (Cpt1a), a key enzyme of beta-oxidation in the liver. This trans-omical analysis also suggested that nicotinamide adenine dinucleotide (NAD) synthesis in the liver may be linked to the occupancy of Lactobacillus through the regulation of nicotinamide phosphoribosyltransferase (NAMPT) and kynureninase (KYNU) genes. Our results suggested that SH condition along with the presence of correlated bacteria species causes weak depression phenotype in young mice and provides a suitable model to study food ingredient that is able to cure weak depression.

Activation of peroxisome proliferator‐activated receptor‐α stimulated lipid catabolism in liver of largemouth bass, Micropterus salmoides

In aquaculture, excess lipid deposition in liver is a health damage in largemouth bass (Micropterus salmoides). Activation of peroxisome proliferator-activated receptor-α (PPARα) has been proved to stimulate lipid catabolism and alleviate fatty liver in rodents and human. Our present study was conducted to investigate the effects of Pparα activation via dietary fenofibrate stimulation on hepatic lipid catabolism in largemouth bass. Total 240 fish (10.7 ± 0.2 g) were randomly divided into eight tanks and fed two diets (control and control containing 5 g/kg fenofibrate), respectively, for 4 weeks. Dietary fenofibrate increased Pparα protein and mitochondrial DNA amounts. The weight gain rate and carcass ratio of fish with Pparα activation decreased, but viscerosomatic index and hepatosomatic index were higher in the fenofibrate-fed fish than the control. Pparα activation significantly reduced triglyceride levels in the serum and liver but did not change the lipid composition in liver. Moreover, hepatic glycogen accumulation was found in the fish with Pparα activation. The Pparα activation also had health benefits for liver, as reflected by reducing serum ALT and AST activities, and increasing antioxidative ability in liver. Our results showed that in largemouth bass, Pparα can be activated and the Pparα activation could efficiently stimulate lipid catabolism and reduce hepatic fat deposition, and promote health in liver.

Histidine optimal supply in dairy cows through determination of a threshold efficiency

Two His deletion studies were conducted to examine the mechanisms used by dairy cows to support milk true protein yield (MTPY) when His supply is altered. The potential mechanisms involved in how the efficiency of utilization of His varied included reduced catabolism, more efficient mammary usage, and use of His labile pools. For the first study, 5 multicatheterized cows were used in a 4 × 4 Latin square plus 1 cow with 14-d periods. Treatments were abomasal infusion of increasing doses of His (0, 7.6, 15.2, and 20.8 g/d) in addition to a mixture of AA (595 g/d; casein profile excluding His). Cows were fed the same protein-deficient diet throughout the study. The MTPY increased linearly with a quadratic tendency with increasing doses of His. Muscle concentrations of carnosine, a His-based dipeptide, tended to increase in a quadratic manner with increasing His supply, suggesting that the 0- and 7.6-g doses were insufficient to cover His requirement. Liver catabolism of His decreased as His supply decreased. Mammary fractional removal of His was considerably greater at low His supply, but the ratio of His mammary net uptake to milk output was not affected by the rate of His infusion, averaging 1.02. The mechanisms to face a reduced His supply included reduced His hepatic catabolism, more efficient His mammary use of lowered arterial supply, and, to a lesser extent, use of His labile pools. Two independent estimates of His efficiency were calculated, one based on the sum of exported proteins (measured MTPY plus estimated metabolic fecal protein and scurf; i.e., the anabolic component, EffMTPY) and the other based on liver removal (i.e., the catabolic component). These 2 estimates followed the same pattern of response to His supply, decreasing with increasing His supply. The EffMTPY at which MTPY peaked was 0.785. For the second study, 6 cows were used in a 6 × 6 Latin square with 7-d periods. Two greater doses of His (30.4 and 38.0 g/d) were added; otherwise, the nutritional design was similar to the first study. In this second study, the indicator AA oxidation technique was used instead of the multiorgan approach, with labeled Leu as the indicator of His utilization. The MTPY peaked and Leu oxidation reached the nadir at an average EffMTPY of 0.763. Combined across both studies, the data indicate that optimal usage of His would occur at a threshold EffMTPY of 0.77. The agreement between experimental approaches across both studies indicates that the biological optimal supply of His expressed in grams per day could be calculated as the sum of exported proteins divided by this EffMTPY plus estimated endogenous urinary excretion.

A natural additive in the diet to improve growth and reduce energy expenditure of gilthead seabream (Sparus aurata L.): Attenuation of high stocking density stress responses

Fish welfare is gaining momentum due to consumers' trends and legal regulations. Therefore, aquaculture industry is in the way of mitigating stress to the animals and, thus, improving the physiological status, with the consequent increase in economical profits. As a consequence, feed additives have been proposed as potential stress relievers through the diet. However, the effectiveness of these extracts on stress responses and growth regulation is still to be defined for different species and stressors. Here we show the effects of the commercial natural-additive “Relaquax” on growth performance, endocrine regulation of hypothalamic-pituitary-interrenal (HPI) and somatotropic (GH/IGF-I) axes, as well as intermediary metabolism, of gilthead seabream (Sparus aurata L.) reared in low and high stocking density conditions. For this purpose, S. aurata juveniles were maintained for 3 months at different combined conditions of feeding (control diet or supplemented with the additive) and initial stocking density (low or high; 4.0 or 11.5 kg m−3, respectively). At the end of the experimental period, brain, pituitary, head kidney and liver gene expression of endocrine factors involved in stress and growth regulation were determined. In addition, liver and muscle enzyme activities of the intermediary metabolism of carbohydrates, lipids and amino acids were assessed. Our results showed an increased growth performance in fish fed with the additive, mediated through hepatic igf1 enhanced expression at both stocking densities. In the same way, higher body mass was associated to inhibition of lipid catabolism in muscle (decreased GPDH and HADH activities), as a consequence of diet supplementation. The additive has also reduced amino acid catabolism in liver (decreased AST activity), as well as enhanced glycolysis in muscle (increased PK activity). In conclusion, this additive was confirmed as a natural alternative to improve aquaculture and welfare of seabream, especially under high stocking density conditions.

Postruminal infusions of amino acids or glucose affect metabolisms of splanchnic, mammary, and other peripheral tissues and drive amino acid use in dairy cows

Effects of AA and glucose infusions on efficiency of use of essential AA (EAA) were studied according to a 2 × 2 factorial using 5 multicatheterized cows in a 4 × 4 Latin square plus one cow, with 2-wk periods. The diet provided 87% of energy and 70% of metabolizable protein requirements, and the 4 treatments were abomasal infusions of (1) water, (2) an AA mixture with a casein profile (695 g/d), (3) glucose (1,454 g/d), or (4) a combination of AA and glucose infusions. Milk samples were collected on the last 6 milkings. On d 14, 6 blood samples were collected from arterial, and portal, hepatic, and mammary venous vessels. Splanchnic plasma flow was calculated by dilution of p-aminohippurate and mammary flow by the Fick principle using Phe + Tyr. The net flux of AA across tissues [splanchnic, i.e., portal-drained viscera (PDV) + liver, and mammary gland] was calculated as the efflux minus the influx across that tissue. The efficiency of EAA was calculated as the sum of exported true proteins [milk protein yield (MPY), scurf, and metabolic fecal protein] multiplied by their respective AA profile and divided by the predicted AA supply minus AA endogenous urinary loss. In addition, catabolism was estimated for each tissue: AA supply - (portal net flux + metabolic fecal protein) for the PDV; -hepatic net flux for the liver; splanchnic net flux- (-mammary net flux + scurf) for the other peripheral tissues; and -mammary net flux - milk for the mammary gland. The MIXED procedure (SAS Institute Inc., Cary, NC) was used with cow as a random effect. No AA × glucose interaction existed for most of the measured parameters. With infusions of AA and glucose, MPY increased by 17 and 14%, respectively. The decreased efficiency of EAA-N with AA infusion resulted from increased EAA-N in MPY smaller than the increased EAA-N supply and was accompanied by increased liver catabolism of His + Met + Phe (representing group 1 AA) and increased mammary and PDV catabolisms of group 2 AA-N (Ile, Leu, Lys, and Val). In contrast, the increased efficiency of EAA-N with glucose infusion, resulting from increased EAA-N in MPY with no change in EAA-N supply, was accompanied by decreased mammary catabolism of group 2 AA-N and hepatic catabolism of His + Met + Phe. No mammary catabolism of His, Met, and Phe existed in all treatments, as indicated by the mammary uptake to milk output ratio close to one for these EAA. Therefore, the mammary gland contributes significantly to variations of efficiency of group 2 AA-N through variations of AA catabolism, in response to both AA and glucose supplies, whereas additional PDV catabolism was observed with increased AA supply. Partition of AA use between tissues allows to delineate their anabolic or catabolic fate across tissues and better understand changes of efficiency of EAA in response to protein and energy supplies.

The comparisons in protective mechanisms and efficiencies among dietary α-lipoic acid, β-glucan and l-carnitine on Nile tilapia infected by Aeromonas hydrophila

Dietary α-lipoic acid (LA), β-glucan (Gluc) and l-carnitine (L-Ca) are commonly used additives to promote fish growth and stress resistance in aquaculture production. However their mechanisms and efficiencies in helping fish to resist diseases have not been compared before. In this study, we fed Nile tilapia (Oreochromis niloticus) with diets containing appropriate doses of LA, Gluc and L-Ca for five weeks and further intraperitoneally injected the fish with Aeromonas hydrophila. After dietary treatment, none of the additives affected the fish growth, but dietary Gluc and L-Ca reduced protein and lipid body contents in fish, respectively. After A. hydrophila challenge, all fish treated with the three dietary additives showed higher survival rate, but those fed on dietary L-Ca had lower survival than those fed on LA and Gluc diets, indicating high protection efficiency of LA and Gluc. The protective mechanisms of the three feed additives were quite different under A. hydrophila infection. Dietary LA induced higher total antioxidant capacity and higher mRNA expression of anti-oxidative genes than other additives in liver and also activated partly the immune function in serum and spleen. Gluc largely increased the immune function by activating the immunity enzymes in serum, inducing inflammation in liver and increasing the expression of immune genes in spleen and head kidney. Gluc also increased partly the antioxidant capacity in serum and liver and lipid catabolism in liver. L-Ca largely increased lipid catabolism in liver while it increased partly the antioxidant capacities in serum and liver. Taken together, these results indicate that, dietary LA, Gluc and L-Ca have various protective mechanisms and differ in their efficiencies on resisting A. hydrophila infection in Nile tilapia.

Berberine alleviates insulin resistance by reducing peripheral branched-chain amino acids.

Increased circulating branched-chain amino acids (BCAAs) have been involved in the pathogenesis of obesity and insulin resistance (IR). However, evidence relating berberine (BBR), gut microbiota, BCAAs, and IR is limited. Here, we showed that BBR could effectively rectify steatohepatitis and glucose intolerance in high-fat diet (HFD)-fed mice. BBR reorganized gut microbiota populations under both the normal chow diet (NCD) and HFD. Particularly, BBR noticeably decreased the relative abundance of BCAA-producing bacteria, including order Clostridiales; families Streptococcaceae, Clostridiaceae, and Prevotellaceae; and genera Streptococcus and Prevotella. Compared with the HFD group, predictive metagenomics indicated a reduction in the proportion of gut microbiota genes involved in BCAA biosynthesis but the enrichment genes for BCAA degradation and transport by BBR treatment. Accordingly, the elevated serum BCAAs of HFD group were significantly decreased by BBR. Furthermore, the Western blotting results implied that BBR could promote the BCAA catabolism in the liver and epididymal white adipose tissues of HFD-fed mice by activation of the multienzyme branched-chain α-ketoacid dehydrogenase complex (BCKDC), whereas by inhibition of the phosphorylation state of BCKDHA (E1α subunit) and branched-chain α-ketoacid dehydrogenase kinase (BCKDK). The ex vivo assay further confirmed that BBR could increase BCAA catabolism in both AML12 hepatocytes and 3T3-L1 adipocytes. Finally, data from healthy subjects and diabetics confirmed that BBR could improve glycemic control and modulate circulating BCAAs. Together, our findings clarified BBR improving IR associated not only with gut microbiota alteration in BCAA biosynthesis but also with BCAA catabolism in liver and adipose tissues.

Effects of a Ketogenic Diet and Chronic Aerobic Exercise on C57BL6 Mice

INTRODUCTIONLow carbohydrate ketogenic diets (LCKD) alter metabolic processes and have been proposed as a means to attenuate adiposity and reduce hyperglycemia. Aerobic exercise training promotes a suite of metabolic adaptations effective in reducing the incidence of metabolic syndrome. There is potential for combined LCKD and aerobic exercise training to alter substrate metabolism in a manner that could enhance body composition. To investigate whether a LCKD could favorably alter metabolic function and potentiate the effects of chronic aerobic exercise, mice were fed a LCKD for a total of 7 weeks, while during the final 3 weeks half of the mice concurrently engaged in daily treadmill exercise.METHODS40 C57BL6 mice were randomized into 4 groups (n=10/group): 2 groups were fed a low‐fat control diet (16% protein, 72% carbohydrate, 12% fat) with one group performing vigorous intensity (blood lactate >4mM post‐exercise) daily treadmill exercise (CEX) and the other serving as sedentary controls (CSED). The remaining 2 groups were fed a LCKD (84% fat, 16% protein) with one exercise group (KEX) and a group of sedentary controls (KSED). Body composition (NMR) was measured weekly. At the end of the 4 week exercise training program, mice were euthanized and substrate oxidation was assessed using 14C labelled substrates, while blood was analyzed for lipids, glucose and β‐OHB.RESULTSThe LCKD resulted in a mild increase in circulating ketones; however, mice on this diet did not exhibit differences in serum fatty acids, triglycerides (TG), or glucose levels despite consuming a lipid‐enriched, carbohydrate‐deficient diet. Body weight and fat mass increased in response to the LCKD, but exercise training limited weight gain. A LCKD did not alter TG levels in liver or muscle; however, exercise training increased TG accrual in both tissues and this effect was more prominent in mice fed the control diet. In the liver, LCKD reduce carbohydrate oxidation, but increased leucine oxidation, incomplete palmitate oxidation, and peroxisomal oxidation. Alternatively, in skeletal muscle carbohydrate oxidation did not change in response to LCKD, whereas mitochondrial and peroxisomal fat oxidation both increased. Exercise training had minimal effect on hepatic substrate oxidation, but increased oxidation of leucine, palmitate, and lignocerate in skeletal muscle; however, no synergistic effects were detected between a ketogenic diet and exercise training.CONCLUSIONOur results indicate that mice fed an 84% fat, 16% protein diet demonstrate a shift in substrate utilization toward an increased reliance on fatty acid and branch‐chain amino acid catabolism in liver and skeletal muscle, while vigorous‐intensity exercise effects were more prominent in muscle. Despite the fact that both LCKD and exercise independently induced shifts in substrate metabolism, the effects do not appear to be additive or synergistic and mice fed an LCKD retained greater adiposity than mice fed a protein‐matched control dietSupport or Funding InformationThis work was supported by NIH R01 DK103860‐01 (R.C.N).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Atherogenic Impact of Lecithin-Cholesterol Acyltransferase and Its Relation to Cholesterol Esterification Rate in HDL (FERHDL) and AIP [log(TG/HDL-C)] Biomarkers: The Butterfly Effect?

The atherogenic impact and functional capacity of LCAT was studied and discussed over a half century. This review aims to clarify the key points that may affect the final decision on whether LCAT is an anti-atherogenic or atherogenic factor. There are three main processes involving the efflux of free cholesterol from peripheral cells, LCAT action in intravascular pool where cholesterol esterification rate is under the control of HDL, LDL and VLDL subpopulations, and finally the destination of newly produced cholesteryl esters either to the catabolism in liver or to a futile cycle with apoB lipoproteins. The functionality of LCAT substantially depends on its mass together with the composition of the phospholipid bilayer as well as the saturation and the length of fatty acyls and other effectors about which we know yet nothing. Over the years, LCAT puzzle has been significantly supplemented but yet not so satisfactory as to enable how to manipulate LCAT in order to prevent cardiometabolic events. It reminds the butterfly effect when only a moderate change in the process of transformation free cholesterol to cholesteryl esters may cause a crucial turn in the intended target. On the other hand, two biomarkers - FER(HDL) (fractional esterification rate in HDL) and AIP [log(TG/HDL-C)] can offer a benefit to identify the risk of cardiovascular disease (CVD). They both reflect the rate of cholesterol esterification by LCAT and the composition of lipoprotein subpopulations that controls this rate. In clinical practice, AIP can be calculated from the routine lipid profile with help of AIP calculator www.biomed.cas.cz/fgu/aip/calculator.php.

Liver BCATm transgenic mouse model reveals the important role of the liver in maintaining BCAA homeostasis

Unlike other amino acids, the branched-chain amino acids (BCAAs) largely bypass first-pass liver degradation due to a lack of hepatocyte expression of the mitochondrial branched-chain aminotransferase (BCATm). This sets up interorgan shuttling of BCAAs and liver–skeletal muscle cooperation in BCAA catabolism. To explore whether complete liver catabolism of BCAAs may impact BCAA shuttling in peripheral tissues, the BCATm gene was stably introduced into mouse liver. Two transgenic mouse lines with low and high hepatocyte expression of the BCATm transgene (LivTg-LE and LivTg-HE) were created and used to measure liver and plasma amino acid concentrations and determine whether the first two BCAA enzymatic steps in liver, skeletal muscle, heart and kidney were impacted. Expression of the hepatic BCATm transgene lowered the concentrations of hepatic BCAAs while enhancing the concentrations of some nonessential amino acids. Extrahepatic BCAA metabolic enzymes and plasma amino acids were largely unaffected, and no growth rate or body composition differences were observed in the transgenic animals as compared to wild-type mice. Feeding the transgenic animals a high-fat diet did not reverse the effect of the BCATm transgene on the hepatic BCAA catabolism, nor did the high-fat diet cause elevation in plasma BCAAs. However, the high-fat-diet-fed BCATm transgenic animals experienced attenuation in the mammalian target of rapamycin (mTOR) pathway in the liver and had impaired blood glucose tolerance. These results suggest that complete liver BCAA metabolism influences the regulation of glucose utilization during diet-induced obesity.

Abstract 1406: High expression of DPD and ALDH1 are associated with poor prognosis in pancreatic cancer

Abstract Background: Pancreatic cancer is a highly aggressive disease and currently the fourth leading cause for cancer related mortality. The annual incidence of it has been shown to be approximately equal to the annual death rate caused by it because of the propensity for early metastatic spread and because the disease is highly resistant to radiation and chemotherapy. Recently, cancer stem cells may play a crucial role in the development and progression of tumor. According to recent studies, cancer stem cell population in human pancreatic cancers are expressing the cell surface markers CD44+, c-Met, and ALDH1. 5-Fluorouracil (5-FU) is one of the key drugs and widely used in the treatment of pancreatic cancer. Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme for 5-FU catabolism in liver, and it was reported that high DPD expression in cancer tissue was associated with 5-FU resistance and poor prognosis. The aim of this study is to examine if the pancreatic cancer stem cells express high DPD as a result acquiring chemoresistance to 5-FU. Methods: A total of 121 patients who underwent curative pancreatectomy for pancreatic cancer from April 2002 to December 2013 were analyzed. Immunohistochemical staining of DPD, ALDH1 and c-Met was performed using paraffin-embedded section of tissues. Expression of them were analyzed in interrelationship each other. Clinical relevance of those markers was confirmed with clinicopathological characteristics that were prospectively collected in our database. Results: Immunohistochemical analysis on clinical sample revealed that DPD expression was high in 55 (45.5%) patients, and high c-Met and ALDH1 expression were seen in 58 (47.9%) and 58 (47.9%) patients retrospectively. ALDH1 activity, DPD expression and sensitivity to 5-FU were examined using pancreatic cancer cell lines in vitro. High DPD expression was significantly associated with high ALDH1 expression not but c-Met, and associated with elderly patients (P = 0.0294) and overall survival (P = 0.0274). Pancreatic cell line with high DPD expression was more resistant to 5-FU than cells with low DPD expression in vitro. Low c-Met expression was significantly associated with high local infiltration (P = 0.0102). ALDH1 expression was significantly associated with relapse free survival (P = 0.0392) and overall survival (P = 0.0358). Conclusion: Our study demonstrated that high DPD expression was significantly associated with specific pancreatic cancer stem cell marker expression, may be involved in resistance to 5-FU treatment in pancreatic cancer. Citation Format: Kota Arima, Hirohisa Okabe, Daisuke Hashimoto, Takayoshi Kaida, Takaaki Higashi, Katsunobu Taki, Hideaki Takeyama, Hidetoshi Nitta, Hiromitsu Hayashi, Akira Chikamoto, Toru Beppu, Hideo Baba. High expression of DPD and ALDH1 are associated with poor prognosis in pancreatic cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1406. doi:10.1158/1538-7445.AM2015-1406

Effect of dietary fish oil on the expression of genes involved in lipid metabolism in liver and skeletal muscle of lactating sows.

This study investigated the hypothesis that dietary supplementation of fish oil as a source of n-3 polyunsaturated fatty acids (PUFA) influences the expression of target genes of sterol regulatory element-binding proteins (SREBP)-1 and (SREBP)-2 involved in triacylglycerol (TAG) synthesis and fatty acid and cholesterol metabolism in the liver, and moreover activates the expression of target genes of peroxisome proliferation-activated receptor (PPAR)-α involved in TAG and fatty acid catabolism in liver and skeletal muscle. Twenty lactating sows were fed a control diet or a fish oil diet with either 50g of a mixture of palm oil and soya bean oil (4:1, w/w) or fish oil per kg. The diet of the fish oil group contained 19.1g of n-3 PUFA (mainly 20:5 n-3 and 22:6 n-3) per 100g of total fatty acids, while the diet of the control group contained 2.4g of n-3 PUFA (mainly 18:3 n-3) per 100g of total fatty acids. The fish oil group had reduced relative mRNA concentrations of various target genes of SREBP-1 involved in fatty acid and TAG synthesis in comparison with the control group (p<0.05). Relative mRNA concentrations of target genes of PPARα involved in fatty acid catabolism in both liver and muscle, and mRNA concentrations of target genes of SREBP-2 involved in cholesterol synthesis and uptake were not influenced by fish oil supplementation. Concentrations of cholesterol and TAG in plasma, fat content of milk and weight gains of litters during the suckling period were not different between the two groups of sows. In conclusion, this study suggests that fish oil has only minor effects on hepatic lipid metabolism, which are non-critical with respect to milk production in sows.

Yeast with bacteriocin from ruminal bacteria enhances glucose utilization, reduces ectopic fat accumulation, and alters cecal microbiota in dietary-induced obese mice.

This study investigated the effect of yeast with bacteriocin (YB) on the homeostasis of lipid and glucose in diet-induced obese (DIO) mice. Seven-week-old C57BL/6 male mice were fed with a Western diet for 24 weeks to induce obesity. These DIO mice were randomly assigned to 2 groups: obese control (WS) and WYB [0.125 μg YB per g body weight (BW)]. YB was administered daily to the WYB mice in the last 4 weeks, while an equal volume of normal saline was administered to the WS mice. YB caused a significant reduction in BW, and in plasma levels of total cholesterol and glucose. Less hepatic lipid accumulation and smaller adipocytes were observed in WYB mice. WYB mice had higher lipid catabolism in liver and adipose tissue. Compared with WS mice, WYB mice had higher glycolysis in the liver and muscles. YB suppressed hepatic GLUT5 expression, altered the composition of cecal microbiota, and also caused more efficient carbohydrate utilization for energy expenditure. YB resulted in body weight loss, promoted lipid catabolism and carbohydrate utilization; it also modulated cecal microbiota, and therefore partially improved the health of obese mice.

A reproductive, developmental and neurobehavioral study following oral exposure of tetrabromobisphenol A on Sprague-Dawley rats.

The objectives of these GLP US EPA OPPTS 970.3800 and 970.3700 studies were to examine the effects of tetrabromobisphenol A (TBBPA) at oral doses of 10, 100 or 1000 mg/kg BW/day over the course of 2 generations on growth as well as behavioral, neurological and neuropathologic functions in offspring. In a separate study the influence of oral TBBPA (0, 100, 300 or 1000 mg/kg BW/d) was examined on embryonic/fetal development from gestation days (GDs) 0-19. In the reproductive study, exposure to ≥ 100-mg/kg BW/d TBBPA resulted in a decrease in circulating, peripheral thyroxine (T4) levels in rats that were not accompanied by any marked alterations in triiodothyronine (T3) and thyroid stimulating hormone (TSH). These findings are explainable on the basis of induction of rat liver catabolism, a phenomenon that may be species-specific and not relevant for humans. TBBPA at up to 1000 mg/kg BW/d was not associated with any significant non-neurological effects on reproduction, growth and development. A subtle reduction, of unknown biological relevance, in the thickness of the parietal cortices of 11-day-old F2 pups in the 1000 mg/kg BW/d group was noted. This change was not accompanied by evidence of micro-anatomic changes. No estrogenic effects sufficient to affect macro and micro anatomy, fertility, reproduction, development, survival or behavior were detected in the embryofetal development study or in the multigenerational study. No other TBBPA-related effects on developmental neurotoxicity/neuropathology were detected. In the developmental study no TBBPA related change in mortality rate was observed in any of the dams. No other significant test article-related effects were noted. The no observed effect level (NOEL) for maternal and developmental toxicity was 1000 mg/kg BW/d, the highest dose evaluated.

A comparison of the effects of oral glutamine dipeptide, glutamine, and alanine on blood amino acid availability in rats submitted to insulin-induced hypoglycemia.

We compared the effects of oral administration of high-dose or low-dose glutamine dipeptide (GDP), alanine (ALA), glutamine (GLN), and ALA + GLN on the blood availability of amino acids in rats submitted to insulin-induced hypoglycemia (IIH). Insulin detemir (1 U/kg) was intraperitoneally injected to produce IIH; this was followed by oral administration of GDP, GLN + ALA, GLN, or ALA. We observed higher blood levels of GLN, 30 min after oral administration of high-dose GDP (1000 mg/kg) than after administration of ALA (381 mg/kg) + GLN (619 mg/kg), GLN (619 mg/kg), or ALA (381 mg/kg). However, we did not observe the same differences after oral administration of low-dose GDP (100 mg/kg) compared with ALA (38.1 mg/kg) + GLN (61.9 mg/kg), GLN (61.9 mg/kg), or ALA (38.1 mg/kg). We also observed less liver catabolism of GDP compared to ALA and GLN. In conclusion, high-dose GDP promoted higher blood levels of GLN than oral ALA + GLN, GLN, or ALA. Moreover, the lower levels of liver catabolism of GDP, compared to ALA or GLN, contributed to the superior performance of high-dose GDP in terms of blood availability of GLN.

Evaluation of a tandem gas chromatography/time-of-flight mass spectrometry metabolomics platform as a single method to investigate the effect of starvation on whole-animal metabolism in rainbow trout (Oncorhynchus mykiss)

This study was conducted to evaluate the use of a two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC/TOF-MS) metabolomic platform to comprehensively analyze the effect of starvation on whole-animal metabolism in rainbow trout (Oncorhynchus mykiss). Trout were either fed a commercial diet at 2% body mass twice daily or starved for 4 weeks. Metabolomic analysis was conducted on serum, liver and muscle tissue from each fish. Database searching and statistical analysis revealed that concentrations of more than 50 positively identified molecules changed significantly (P<0.05) as a result of starvation. Our results indicate that starving rainbow trout for 4 weeks promotes increased utilization of select tissue fatty acids in liver and muscle. However, starvation did not significantly affect protein catabolism in peripheral tissues, as indicated by reductions in the level of serum amino acids in starved fish. In contrast, starvation appears to promote protein catabolism in liver as the level of methionine, proline and lysine metabolite 2-piperidine carboxylic acid increased significantly. Also, starvation resulted in significant changes in the level of numerous xenobiotics that could indicate the origin of particular feed ingredients and selective retention of these molecules in tissues. We suggest that metabolomic analysis using GC×GC/TOF-MS is an effective tool in studying whole-animal metabolism and the fate of important xenobiotic compounds in rainbow trout as numerous polar and non-polar metabolites were rapidly and accurately profiled using a single method.

Abstract 1869: Severe toxicities in patients undergoing gemcitabine, ARA-C, capecitabine, or azacytidine treatments: Is deregulated cytidine deaminase the bad guy

Abstract Background: Nucleoside analogs are anticancer drugs widely used both in adults and in children. Genetic polymorphisms leading to impaired ability to detoxify drugs in the liver are a major issue in clinical oncology. Cytidine deaminase (CDA) is a ubiquituous enzyme responsible for the metabolism of several pyrimidine derivatives. CDA is involved in the activation pattern of capecitabine, but conversely is responsible for the liver catabolism of most other nucleosidic analogs. So far, downregulated CDA is considered as an issue with gemcitabine, but little is known about the impact of deregulated CDA on the clinical outcome with other pyrimidine analogs. Methods: A retrospective study was perfomed as a proof-of-concept for the implication of CDA in severe toxicities with several pyrimidine analogs. Phenotypic and genotypic investigations were performed in a subset of patients presenting with severe toxicities soon after being treated for the first time with a pyrimidine derivative. CDA status was evaluated on a phenotypic basis using a surrogate enzymatic test. Additionally, polymorphisms associated with loss of CDA activity (i.e. 79A&amp;gt;C, 435 T&amp;gt;C, 208 G&amp;gt;A mutations) or conversely with increased expression (i.e. rs532545 deletion) were screened. Toxicities were monitored following the standard CTC 4.0 grading. Results &amp; Discussion: We followed five patients (4 adults, 1 child), all presenting with extremely severe toxicities soon after being treated with a nucleoside analog (i.e. capecitabine, gemcitabine, azacytidine and ara-C, respectively). Two patients treated with capecitabine underwent severe toxicities, including a lethal one. Both patients were phenotyped as CDA ultra-metabolizer (UM: CDA &amp;gt; 6 U/mg). The rs532545 deletion in the CDA promoter region was found in the patient with lethal outcome. This suggests that CDA UM status triggers toxicities through an increased activation of capecitabine towards its toxics metabolites. Conversely, poor metabolizer (PM) profile (i.e. CDA &amp;lt; 2 U/mg) was evidenced in the 3 other patients with severe toxicities upon gemcitabine, azacytidine and Ara-C intake. Of note, one of the patient exhibited the double 79A&amp;gt;C and rs532545 polymorphisms, which have opposite impacts on CDA levels eventually. In this case, phenotypic determination proved to be critical to picture the CDA status, and confirmed her PM phenotype. Our observations suggest that CDA deficiency makes patients administered with gemcitabine, azacytidine and ara-C at risk of early severe toxicities alike. Conclusions: Deregulated CDA (i.e. PM or UM patients) proved to be associated with a serial of severe/lethal toxicities in patients treated with nucleoside analogs frequently administered in clinical oncology. Overall, this POC study warrants the identification of CDA status in patients prior to starting pyrimidine-based treatments. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1869. doi:1538-7445.AM2012-1869

Mangiferin Decreases Plasma Free Fatty Acids through Promoting Its Catabolism in Liver by Activation of AMPK

Mangiferin has been shown to have the effect of improving dyslipidemia. Plasma free fatty acids (FFA) are closely associated with blood lipid metabolism as well as many diseases including metabolic syndrome. This study is to investigate whether mangiferin has effects on FFA metabolism in hyperlipidemic rats. Wistar rats were fed a high-fat diet and administered mangiferin simultaneously for 6 weeks. Mangiferin (50, 100, 150 mg/kg BW) decreased dose-dependently FFA and triglycerides (TG) levels in plasma, and their accumulations in liver, but increased the β-hydroxybutyrate levels in both plasma and liver of hyperlipidemic rats. HepG2 cells were treated with oleic acid (OA, 0.2 mmol/L) to simulate the condition of high level of plasma FFA in vitro, and were treated with different concentrations of mangiferin simultaneously for 24 h. We found that mangiferin significantly increased FFA uptake, significantly decreased intracellular FFA and TG accumulations in HepG2 cells. Mangiferin significantly increased AMP-activated protein kinase (AMPK) phosphorylation and its downstream proteins involved in fatty acid translocase (CD36) and carnitine palmitoyltransferase 1 (CPT1), but significantly decreased acyl-CoA: diacylgycerol acyltransferase 2 (DGAT2) expression and acetyl-CoA carboxylase (ACC) activity by increasing its phosphorylation level in both in vivo and in vitro studies. Furthermore, these effects were reversed by Compound C, an AMPK inhibitor in HepG2 cells. For upstream of AMPK, mangiferin increased AMP/ATP ratio, but had no effect on LKB1 phosphorylation. In conclusion, mangiferin decreased plasma FFA levels through promoting FFA uptake and oxidation, inhibiting FFA and TG accumulations by regulating the key enzymes expression in liver through AMPK pathway. Therefore, mangiferin is a possible beneficial natural compound for metabolic syndrome by improving FFA metabolism.

13C magnetic resonance spectroscopy detection of changes in serine isotopomers reflects changes in mitochondrial redox status

The glycine cleavage system (GCS), the major pathway of glycine catabolism in liver, is found only in the mitochondria matrix and is regulated by the oxidized nicotinamide adenine dinucleotide (NAD(+) )/reduced nicotinamide adenine dinucleotide (NADH) ratio. In conjunction with serine hydroxymethyltransferase, glycine forms the 1 and 2 positions of serine, while the 3 position is formed exclusively by GCS. Therefore, we sought to exploit this pathway to show that quantitative measurements of serine isotopomers in liver can be used to monitor the NAD(+) /NADH ratio using (13) C NMR spectroscopy. Rat hepatocytes were treated with modulators of GCS activity followed by addition of 2-(13) C-glycine, and the changes in the proportions of newly synthesized serine isotopomers were compared to controls. Cysteamine, a competitive inhibitor of GCS, prevented formation of mitochondrial 3-(13) C-serine and 2,3-(13) C-serine isotopomers while reducing 2-(13) C-serine by 55%, demonstrating that ca. 20% of glycine-derived serine is produced in the cytosol. Glucagon, which activates GCS activity, and the mitochondrial uncoupler carbonyl cyanide-3-chlorophenylhydrazone both increased serine isotopomers, whereas rotenone, an inhibitor of complex I, had the opposite effect. These results demonstrate that (13) C magnetic resonance spectroscopy monitoring of the formation of serine isotopomers in isolated rat hepatocytes given 2-(13) C-glycine reflects the changes of mitochondrial redox status.