Influence of different dietary fats on triacylglycerol deposition in rat adipose tissue

It has been demonstrated that triacylglycerol (TAG) mobilization from adipose tissue is selective and depends on fatty acid (FA) chain length, unsaturation and positional isomerism. The present study was performed to determine the influence of dietary fat on the composition of TAG stored in rat perirenal and subcutaneous adipose tissues. These results may provide information on the susceptibility of stored TAG to hydrolysis and further mobilization, and may help to establish an interrelationship between dietary composition and the FA efflux from adipose tissue. TAG molecular species and FA composition were determined by HPLC and GLC respectively. No significant differences were found in either FA or TAG composition between perirenal and subcutaneous adipose depots. The major FA in the dietary fats were present in the adipose tissues of the animals; in most cases, in similar proportions. However, differences were found between dietary and adipose tissue content of minor FA, which suggests that dietary FA composition is altered between ingestion and deposition in adipose tissue. The TAG molecular species of rat adipose tissue were enriched with the FA characteristic of each dietary fat. Dietary sunflower oil was responsible for enrichment with the most polar TAG. This finding may suggest easier mobilization of stored TAG. In conclusion, the process of fatty acid and TAG deposition in rat adipose tissue is selective, and depends on the composition of the diet.Supported by grants (OLI96-2126 and ALI99-0863) from the Comisión Interministerial de Ciencia y Tecnología (CICYT) and the Government of the País Vasco (PI 96/22) and by a felIowship from this Government

Features of Non-Alcoholic Beer on Cardiovascular Biomarkers. Can It Be a Substitute for Conventional Beer?

Numerous studies have revealed the beneficial effects of moderate beer consumption on cardiovascular diseases. However, the presence of alcohol in beer can represent a matter of concern, since alcohol intake poses a risk to some individuals. Additionally, adults who are life-long abstainers should not be encouraged to consume alcohol for health purposes. Consequently, the benefits of beer consumption remain a controversial issue. In this scenario, the present review gathers the reported information concerning the cardiovascular effects of non-alcoholic beer, and makes a comparison between these effects and those of conventional beer. Despite the scarcity of published results to date describing the effects of non-alcoholic beer consumption, the available literature indicates that it is more effective than conventional beer in preventing oxidative stress (lower lipid and protein oxidation), preserving the endothelial function (lower endothelial dysfunction) and inhibiting thrombogenic activity (lowered oxidized LDL). By contrast, conventional beer has shown to induce greater increases in HDL-cholesterol levels (known as a cardiovascular protective factor) compared to non-alcoholic beer. This effect cannot be solely attributed to alcohol content, since the polyphenol content in conventional beer tends to be higher than that found in non-alcoholic beer.This research was funded by CIBEROBN under Grant CB12/03/30007 and the Government of the Basque Country (IT1482-22)

Effects of trans-10, cis-12 conjugated linoleic acid on the expression of uncoupling proteins in hamsters fed an atherogenic diet

It is known that conjugated linoleic acid (CLA) feeding decreases body adiposity but the mechanisms involved are not clear. The aim of this study was to analyse whether alterations in uncoupling protein (UCP) expression in white and brown adipose tissues (WAT and BAT, respectively) and in skeletal muscle may be responsible for the effect of trans-10, cis-12 CLA on the size of body fat depots in hamsters. Animals were divided into three groups and fed an atherogenic diet with different amounts of trans-10, cis-12 CLA (0 control, 0·5, or 1 g/100 g diet) for 6 weeks. CLA feeding reduced adipose depot weights, but had no effect on body weight. Leptin mRNA expression decreased in both subcutaneous and perirenal WAT depots, in accordance with lower adiposity, whereas resistin mRNA expression was not changed. Animals fed CLA had lower UCP1 mRNA levels in BAT (both doses of CLA) and in perirenal WAT (the low dose), and lower UCP3 mRNA levels in subcutaneous WAT (the high dose). UCP2 mRNA expression in WAT was not significantly affected by CLA feeding. Animals fed the high dose of CLA showed increased UCP3 and carnitine palmitoyl transferase-I (CPT-I) mRNA expression levels in skeletal muscle. In summary, induction of UCP1 or UCP2 in WAT and BAT is not likely to be responsible for the fat-reduction action of CLA, but the increased expression of UCP3 in skeletal muscle, together with a higher expression of CPT-I, may explain the previously reported effects of dietary CLA in lowering adiposity and increasing fatty acid oxidation by skeletal muscle

Relationship between changes in microbiota induced by resveratrol and its anti-diabetic effect on type 2 diabetes

Although a general healthy gut microbiota cannot be defined due to numerous internal and external individual factors, such as sex, age, ethnicity, genetics, environment, diet and drugs affect its composition, certain microbial species and gut microbiota compositions seem to be related to the progression of insulin resistance to type 2 diabetes, as well as the development of microvascular and macrovascular complications of diabetes. The present review aimed at gathering the reported information describing how resveratrol induced changes in microbiota composition can mediate the positive effects of this polyphenol on glucose homeostasis under type 2 diabetic conditions, both in animals and humans. Based on the fact that some changes observed in the gut microbiota of type 2 diabetic animals and patients are reversed by resveratrol treatment, and taking into account that some resveratrol mediated changes in gut microbiota composition are similar to those induced by anti-diabetic drugs such as metformin, it can be proposed that four genera, Alistipes, Allobaculum, Desulfovibrio and Blautia could be involved in the benefits of resveratrol on glycameic control. Nevertheless some limitations are observed in this research field: (a) the number of studies analyzing both the effects of resveratrol on glucose homeostasis and microbiota composition in the same cohort of animals, in order to know the potential involvement of microbiota in the anti-diabetic effects of this phenolic compound, are very scarce and practically inexistent in the case of humans., (b) the studies present inconsistencies concerning the effects of resveratrol on gut microbiota changes, (c) the experimental design used do not allow the researchers to establish a causal relationship between the changes in microbiota and the anti-diabetic effect, in the vast majority of the studies, (d) the knowledge about the role of each type of bacteria on glycaemic control is not sufficient so far.This study was supported by Instituto de Salud Carlos III (CIBERobn) under Grant CB12/03/30007 and the Government of the Basque Country (IT1482-22)

Lactobacillus rhamnosus GG administration partially prevents diet-induced insulin resistance in rats: a comparison with its heat-inactivated parabiotic

Insulin resistance and type 2 diabetes are obesity-related health alterations, featuring an ever-increasing prevalence. Besides inadequate feeding patterns, gut microbiota alterations stand out as potential contributors to these metabolic disturbances. The aim of this study was to investigate whether the administration of a probiotic (Lactobacillus rhamnosus GG) effectively prevents diet-induced insulin resistance in rats and to compare these potential effects with those exerted by its heat-inactivated parabiotic. For this purpose, 34 male Wistar rats were fed a standard or a high-fat high-fructose diet, alone or supplemented with viable or heat-inactivated Lactobacillus rhamnosus GG. The body and white adipose tissue weight increases, induced by the obesogenic diet, were prevented by probiotic and parabiotic administration. The trend towards higher basal glucose levels and significantly higher serum insulin concentration observed in the non-treated animals fed with the obesogenic diet were effectively reverted by both treatments. Similar results were also found for serum adiponectin and leptin, whose levels were brought back by the probiotic and parabiotic administration to values similar to those of the control animals. Noteworthily, parabiotic administration significantly reduced skeletal muscle triglyceride content and activated CPT-1b compared to the non-treated animals. Finally, both treatments enhanced Akt and AS160 phosphorylation in the skeletal muscle compared to the non-treated animals; however, only parabiotic administration increased GLUT-4 protein expression in this tissue. These results suggest that heat-inactivated Lactobacillus rhamnosus GG seem to be more effective than its probiotic of origin in preventing high-fat high-fructose diet-induced insulin resistance in rats.This study was supported by Instituto de Salud Carlos III (CIBERobn) under grant CB12/03/30007 and The Basque Government under grant IT1482-22. Laura Isabel Arellano-García is a recipient of a doctoral fellowship from the Gobierno Vasco

Changes in white adipose tissue metabolism induced by resveratrol in rats

Background: A remarkable range of biological functions have been ascribed to resveratrol. Recently, this polyphenol has been shown to have body fat lowering effects. The aim of the present study was to assess some of the potential underlying mechanisms of action which take place in adipose tissue. Methods: Sixteen male Sprague-Dawley rats were randomly divided into two groups: control and treated with 30 mg resveratrol/kg body weight/d. All rats were fed an obesogenic diet and after six weeks of treatment white adipose tissues were dissected. Lipoprotein lipase activity was assessed by fluorimetry, acetyl-CoA carboxylase by radiometry, and malic enzyme, glucose-6P-dehydrogenase and fatty acid synthase by spectrophotometry. Gene expression levels of acetyl-CoA carboxylase, fatty acid synthase, lipoprotein lipase, hormone-sensitive lipase, adipose triglyceride lipase, PPAR-gamma, SREBP-1c and perilipin were assessed by Real time RT-PCR. The amount of resveratrol metabolites in adipose tissue was measured by chromatography. Results: There was no difference in the final body weight of the rats; however, adipose tissues were significantly decreased in the resveratrol-treated group. Resveratrol reduced the activity of lipogenic enzymes, as well as that of heparin-releasable lipoprotein lipase. Moreover, a significant reduction was induced by this polyphenol in hormone-sensitive lipase mRNA levels. No significant changes were observed in other genes. Total amount of resveratrol metabolites in adipose tissue was 2.66 +/- 0.55 nmol/g tissue. Conclusions: It can be proposed that the body fat-lowering effect of resveratrol is mediated, at least in part, by a reduction in fatty acid uptake from circulating triacylglycerols and also in de novo lipogenesis.This study was supported by grants from the Ministerio de Ciencia e Innovacion (AGL2008-1005-ALI and partially by the AGL2006-14228-C03-02), Instituto de Salud Carlos III (RETIC PREDIMED) and the Government of Pais Vasco (IT-386-10; CTP09/R5). G. Alberdi is a recipient of a doctoral fellowship from the Ministerio de Ciencia e Innovacion. Resveratrol was a generous gift from Monteloeder (Elche, Alicante, Spain)

trans-10, cis-12 Conjugated linoleic acid inhibits lipoprotein lipase but increases the activity of lipogenic enzymes in adipose tissue from hamsters fed an atherogenic diet

The aim of the present work was to investigate the effects of trans-10,cis-12conjugated linoleic acid (CLA) on the activity and expression of lipogenic enzymes and lipoprotein lipase (LPL), as well as on the expression of transcriptional factors controlling these enzymes, in adipose tissue from hamsters, and to evaluate the involvement of these changes in the body fat-reducing effect of this CLA isomer. Thirty male hamsters were divided into three groups and fed atherogenic diets supplemented with 0 (linoleic group), 5 or 10g trans-10,cis-12CLA/kg diet, for 6 weeks. Body and adipose tissue weights, food intake and serum insulin were measured. Total and heparin-releasable LPL and lipogenic enzyme activities (acetyl-CoA carboxylase (ACC); fatty acid synthase (FAS); glucose-6-phosphate dehydrogenase (G6PDH); and malic enzyme (ME)) were assessed. ACC, FAS, LPL, sterolregulatory element-binding proteins (SREBP-1a), SREBP-1c and PPARγ mRNA levels were alsodetermined by real-time PCR. CLA did not modify food intake, body weight and serum insulin level. CLA feeding reduced adipose tissue weight, LPL activity and expression, and increased lipogenic enzyme activities, despite a significant reduction in ACC and FAS mRNA levels. The expression of the three transcriptional factors analysed (SREBP-1a, SREBP-1c and PPARγ) wasalso reduced. These results appear to provide a framework for partially understanding the reduction in body fat induced by CLA. Inhibition of LPL activity seems to be an important mechanism underlying body fat reduction in hamsters. Further research is needed to better characterizethe effects of CLA on lipogenesis and the role of these effects in CLA action

Potential Usefulness of a Wakame/Carob Functional Snack for the Treatment of Several Aspects of Metabolic Syndrome: From In Vitro to In Vivo Studies

Metabolic syndrome (MetS) greatly increases the risk of cardiovascular diseases and type 2 diabetes mellitus. The aim of this study was to evaluate the efficacy of functional snacks containing a combination of wakame (W) and carob pod (CP) flours in reducing markers associated with MetS. The mechanisms of action underlying these effects were also evaluated. In vitro approaches were carried out in mature 3T3-L1 adipocytes and RAW 264.7 macrophages treated with different doses of extracts from W, CP, or a combination of both. Furthermore, an in vivo experiment was conducted in rats with MetS treated with normal-caloric diets containing different snack formulations with combinations of 1/50 (snack A) or 1/5 of wakame/carob (snack B). In vitro experiments results indicated that both W and CP had delipidating effects, but only the latter induced anti-inflammatory and anti-hypertensive effects. As far as the in vivo study is concerned, snack B was ineffective and snack A showed an anti-hypertensive effect in rats with MetS. The present study shows for the first time the in vitro efficacy of a W and CP combination as an anti-inflammatory, delipidating, and anti-hypertensive tool, and its potential usefulness in treating MetS.This study has been supported by the National Institute for Agricultural and Food Research and Technology of Spain (INIA: RTA2014-0037-C02), University of the Basque Country (ELDUNANOTEK UFI11/32), Instituto de Salud Carlos III (CIBERobn), and the Basque Government (IT-572-13)

Effects of trans-10, cis-12 conjugated linoleic acid on the expression of uncoupling proteins in hamsters fed an atherogenic diet

It is known that conjugated linoleic acid (CLA) feeding decreases body adiposity but the mechanisms involved are not clear. The aim of this study was to analyse whether alterations in uncoupling protein (UCP) expression in white and brown adipose tissues (WAT and BAT, respectively) and in skeletal muscle may be responsible for the effect of trans-10, cis-12 CLA on the size of body fat depots in hamsters. Animals were divided into three groups and fed an atherogenic diet with different amounts of trans-10, cis-12 CLA (0 control, 0·5, or 1 g/100 g diet) for 6 weeks. CLA feeding reduced adipose depot weights, but had no effect on body weight. Leptin mRNA expression decreased in both subcutaneous and perirenal WAT depots, in accordance with lower adiposity, whereas resistin mRNA expression was not changed. Animals fed CLA had lower UCP1 mRNA levels in BAT (both doses of CLA) and in perirenal WAT (the low dose), and lower UCP3 mRNA levels in subcutaneous WAT (the high dose). UCP2 mRNA expression in WAT was not significantly affected by CLA feeding. Animals fed the high dose of CLA showed increased UCP3 and carnitine palmitoyl transferase-I (CPT-I) mRNA expression levels in skeletal muscle. In summary, induction of UCP1 or UCP2 in WAT and BAT is not likely to be responsible for the fat-reduction action of CLA, but the increased expression of UCP3 in skeletal muscle, together with a higher expression of CPT-I, may explain the previously reported effects of dietary CLA in lowering adiposity and increasing fatty acid oxidation by skeletal muscle

Dietary fat source regulates ob gene expression in white adipose tissue of rats under hyperphagic feeding

This work was designed to investigate the effect of different lipid sources on ob gene expression and serum leptin levels in rats with two different feeding protocols: (1) free access to food; or (2) energy-controlled feeding. Male Wistar rats were fed diets containing 40 % energy as fat (olive oil, sunflower oil or beef tallow), for 4 weeks. In Expt 1 rats had free access to food, and in Expt 2 rats were fed a controlled amount of food (16 g/d, equivalent to 300 kJ/d). Insulin and leptin were determined by ELISA and ob mRNA by Northern blot. When rats had free access to food, ob mRNA levels were higher in animals fed either olive oil or sunflower oil than in those fed beef tallow. In marked contrast with feeding ad libitum, no differences were found among dietary fat groups in rats fed energy-controlled diets. When both feeding protocols were compared, free access to food induced an increased expression of ob mRNA in perirenal and/or epididymal adipose tissues from rats fed either olive oil or sunflower oil, but not from rats fed beef tallow. Dietary lipid type did not induce modifications in serum leptin concentrations. A tendency to higher serum leptin levels was observed more in rats with free access to food than in rats fed energy-controlled feeding. No differences were found in insulin levels. Dietary fat type importantly affects ob mRNA expression in rat white adipose tissue under hyperphagic conditions. Further study is needed in order to elucidate the mechanism underlying this effect.Supported by the Government of the País Vasco (grant PI 96/22 to M.P.P.), DGICYT, Ministerio de Educación y Ciencia, Spain (grant PM97-0094 to AP.) and by the European Commission DGXII (COST 918 to AP.). V.M.R. is a recipient of a fellowship from the Spanish Government