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Recent studies have associated several microRNAs (miRNAs) with childhood obesity and energy homeostasis, suggesting that an individual miRNA profile could be used as an early predictor to estimate the response to weight loss interventions in the design of precision nutrition.To investigate associations between the expression of circulating adiposity-related miRNAs and the response to a weight loss intervention.A total of 51 Spanish girls (age 7-16 years) with abdominal obesity underwent 8 weeks of a multidisciplinary intervention for weight loss. Participants were stratified into two groups in accordance with changes in body mass index (BMI) standard deviation score: low-responders (LR) and high-responders (HR). The expression of 39 circulating miRNAs (c-miRNAs) was evaluated in plasma of all subjects before the intervention.Six miRNAs were differentially expressed between LR and HR. However, after adjustment for Tanner stage, the association was maintained only for miR-126-3p and miR-221-3p with a higher expression in HR group compared to LR group. After the intervention, miR-221-3p expression decreased in all subjects with a significant difference in the change within groups. However, changes in miR-126-3p levels were not significant. The expression of miR-221-3p was positively correlated with body weight, BMI and waist circumference, and negatively correlated with quantitative insulin sensitivity check index.Bioinformatic analysis evidenced that miR-221-3p participates in several obesity-related pathways, and more interestingly, this miRNA targets several candidate genes to childhood obesity according to DisGeNet database. Thus, miR-221-3p could be used for predicting the response to a multidisciplinary intervention for weight loss in young girls.

Recent studies have revealed the critical role of several microRNAs (miRNAs) in energy homeostasis and metabolic processes and suggest that circulating miRNAs can be used as early predictors of weight loss in the design of precision nutrition. Thus, the aim of this study was to investigate circulating adiposity‐related miRNAs as biomarkers of the response to two specific weight loss dietary treatments. The expression of 86 miRNAs was investigated in plasma of 78 subjects with obesity randomized to two different diets [moderately high‐protein diet (n = 38) and low‐fat diet (n = 40)] and in 25 eutrophic controls (BMI ≤ 25 kg/m2). Bioinformatic analyses were performed to explore the target genes and biological pathways regulated by the dysregulated miRNAs. As results, 26 miRNAs were found differently expressed in eutrophic and volunteers with obesity. Moreover, 7 miRNAs (miR‐130a‐3p, miR‐142‐5p, miR‐144‐5p, miR‐15a‐5p, miR‐22‐3p, miR‐221‐3p and miR‐29c‐3p) were differentially expressed between responders and non‐responders to a low‐fat diet. Furthermore, after adjustment for basal glucose levels, 1‐SD increase in miR‐22‐3p expression was associated with reduction in the risk of non‐response to low‐fat diet [OR = 0.181, 95% CI (0.084‐0.947), P = .043]. Bioinformatic analyses evidenced that these 7 miRNAs regulate the expression of genes participating in important metabolic pathways. Conclusively, 7 circulating miRNAs related to adiposity could be used for predicting the response to a low‐fat diet intervention prescribed to lose weight.

SummaryBackground The global prevalence of childhood overweight and obesity has increased in the last years. Epigenetic dysregulation affecting gene expression could be a determinant in early-life obesity onset and accompanying complications. Objective The aim of the present investigation was to analyse the putative association between DNA methylation and childhood obesity. Methods DNA was isolated from white blood cells of 24 children obtained from the GENOI study and was hybridized in a 450K methylation array. Two CpG sites associated with obesity were validated in 91 children by MassArray® EpiTyper™ technology. Results Genome-wide analysis identified 734 CpGs (783 genes) differentially methylated between cases (n = 12) and controls (n = 12). Ingenuity Pathway Analysis showed that these genes were involved in oxidative stress and circadian rhythm signalling pathways. Moreover, the DNA methylation levels of VIPR2, GRIN2D, ADCYAP1R1, PER3 and PTPRS regions correlated with the obesity trait. EpiTyper™ validation also identified significant correlations between methylation levels of CpG sites on PTPRS and PER3 with BMI z-score. Conclusions This study identified several CpG sites and specifically several CpGs in the PTPRS and PER3 genes differentially methylated between obese and non-obese children, suggesting a role for DNA methylation concerning development of childhood obesity.

Resveratrol (RSV) has been proposed as an energy restriction mimetic. This study aimed to compare the effects of RSV and energy restriction on insulin resistance induced by an obesogenic diet. Any additive effect of both treatments was also analyzed. Rats were fed a high-fat high-sucrose diet for 6 weeks. They were then distributed in four experimental groups which were either fed a standard control diet (C), or treated with RSV (30 mg/kg/d), or submitted to energy restriction (R, 15%), or treated with RSV and submitted to energy restriction (RR). A glucose tolerance test was performed, and serum glucose, insulin, fructosamine, adiponectin, and leptin concentrations determined. Muscle triacylglycerol content and protein expression of insulin receptor (IRβ), protein kinase B (Akt), Akt substrate of 160 kDa (AS160) and glucose transporter 4 (GLUT-4) were measured. In RSV rats, fructosamine concentrations were reduced, HOMA-IR remained unchanged, but glucose tolerance was improved, without changes in phosphorylation of IRβ, Akt, and AS160 or in GLUT-4 protein expression. Rats under energy restriction showed an improvement in all the markers related to glycemic control, as well as increased phosphorylation of AS160 and protein expression of GLUT-4. In rats from RR group the results were similar to R group, with the exception of IRβ and Akt phosphorylation, which were increased. In conclusion, mild energy restriction is more efficient than intake of RSV within a standard balanced diet, and acts by means of a different mechanism from that of RSV. No additive effects between RSV and energy restriction were observed. © 2017 BioFactors, 43(3):371-378, 2017.

SummaryBackground Epigenetic mechanisms may be involved in obesity onset and its consequences. The aim of the present study was to evaluate whether DNA methylation status in microRNA (miRNA) coding regions is associated with childhood obesity. Material and Methods DNA isolated from white blood cells of 24 children (identification sample: 12 obese and 12 non-obese) from the Grupo Navarro de Obesidad Infantil study was hybridized in a 450 K methylation microarray. Several CpGs whose DNA methylation levels were statistically different between obese and non-obese were validated by MassArray® in 95 children (validation sample) from the same study. Results Microarray analysis identified 16 differentially methylated CpGs between both groups (6 hypermethylated and 10 hypomethylated). DNA methylation levels in miR-1203, miR-412 and miR-216A coding regions significantly correlated with body mass index standard deviation score (BMI-SDS) and explained up to 40% of the variation of BMI-SDS. The network analysis identified 19 well-defined obesity-relevant biological pathways from the KEGG database. MassArray® validation identified three regions located in or near miR-1203, miR-412 and miR-216A coding regions differentially methylated between obese and non-obese children. Conclusions The current work identified three CpG sites located in coding regions of three miRNAs (miR-1203, miR-412 and miR-216A) that were differentially methylated between obese and non-obese children, suggesting a role of miRNA epigenetic regulation in childhood obesity.

Chronic inflammation is involved in the onset and development of many diseases, including obesity, atherosclerosis, type 2 diabetes, osteoarthritis, autoimmune and degenerative diseases, asthma, periodontitis, and cirrhosis. The inflammation process is mediated by chemokines, cytokines, and different inflammatory cells. Although the molecules and mechanisms that regulate this primary defense mechanism are not fully understood, recent findings offer a putative role of noncoding RNAs, especially microRNAs (miRNAs), in the progression and management of the inflammatory response. These noncoding RNAs are crucial for the stability and maintenance of gene expression patterns that characterize some cell types, tissues, and biologic responses. Several miRNAs, such as miR-126, miR-132, miR-146, miR-155, and miR-221, have emerged as important transcriptional regulators of some inflammation-related mediators. Additionally, little is known about the involvement of long noncoding RNAs, long intergenic noncoding RNAs, and circular RNAs in inflammation-mediated processes and the homeostatic imbalance associated with metabolic disorders. These noncoding RNAs are emerging as biomarkers with diagnosis value, in prognosis protocols, or in the personalized treatment of inflammation-related alterations. In this context, this review summarizes findings in the field, highlighting those noncoding RNAs that regulate inflammation, with emphasis on recognized mediators such as TNF-α, IL-1, IL-6, IL-18, intercellular adhesion molecule 1, VCAM-1, and plasminogen activator inhibitor 1. The down-regulation or antagonism of the noncoding RNAs and the administration of exogenous miRNAs could be, in the near future, a promising therapeutic strategy in the treatment of inflammation-related diseases.—Marques-Rocha, J. L., Samblas, M., Milagro, F. I., Bressan, J., Martínez, J. A., Marti, A. Noncoding RNAs, cytokines, and inflammation-related diseases. Inflammation is a complex protective process that requires a cross-talk between different types of immune cells to remove or neutralize harmful stimuli (1). In the classic view, the inflammatory process is induced by an invasion of foreign pathogens of biologic origin or by tissue damage. Neutrophils, dendritic cells, and macrophages express almost all types of TLRs participating in the transmission of a signal from the plasma membrane through a multistep cascade to responsive transcription factors. Members of the TLR family have emerged as the primary evolutionarily conserved sensors of pathogen-associated molecular patterns (1). Binding of the TLRs to their respective ligands initiates a wide spectrum of responses, from phagocytosis to production of a variety of cytokines, which in turn shape and enhance the inflammatory and adaptive immune responses. Typical transcription factors that activate inflammatory mediators are NF-κB (2), activator protein 1 (3), signal transducer and activator of transcription (STAT) (4), CCAAT enhancer binding protein (C/EBP) (5), and Ets-like gene 1 (6). The interactions between transcription factors that compete for binding sites in the promoter regions of specific target genes are highly complex. Usually the multistep signaling leads to a prompt transcription of genes resulting in accumulation of specific mRNAs coding for TNF-α, IL-1, IL-6, IL-8, monocyte chemotactic protein 1 (MCP-1), and other cytokines involved in inflammation (7). Some cytokines may elicit a broad inflammatory response, while others act on specific cell types. The activation, proliferation, and recruitment phenomena of specific differentiated immune cells are involved in resolving the nonhomeostatic state [for a review, see Shi (8)]. Thus, macrophages stimulate the inflammatory responses of neutrophils, fibroblasts, and endothelial cells (2). Other sentinel cells may present antigens to the T-helper cells, which play a central role in coordinating immune responses, such as clonal expansion of T cells and B cell responses (9). Acute inflammation is an important part of the immune response, but chronic inappropriate inflammation can cause metabolic disorders (10). For example, chronic low-grade inflammation has been repeatedly associated with the onset and prevalence of metabolic syndrome (11, 12). The International Diabetes Federation estimates that one quarter of the world’s adult population has metabolic syndrome (13). This phenomenon is defined by a combination of interconnected cardiometabolic alterations that include the presence of arterial hypertension, insulin resistance, dyslipidemia, cardiovascular disease, and abdominal obesity (11). With the pathologic enlargement of the adipose tissue in obesity, the blood supply to adipocytes may be reduced, with subsequent hypoxia leading to a an elevated production of proinflammatory mediators [TNF-α and IL-6, plasminogen activator inhibitor-1 (PAI-1), and C-reactive protein (CRP)] and increased infiltration of immune cells, particularly adipose tissue macrophages (14, 15). These altered signals mediate multiple processes, including insulin sensitivity (16), oxidative stress (17), energy metabolism, blood coagulation, and inflammatory responses (12). These pathologic conditions predispose to diabetes mellitus, hepatic steatosis, atherosclerosis, plaque rupture, and atherothrombosis (11). However, to date, the available information is controversial and does not necessarily imply an unequivocal causal role. The data obtained by functional genomics techniques indicate that several hundreds of genes participate in the inflammatory response and that their coordinated expression is tightly regulated [reviewed in Jura and Koj (18)]. Nevertheless, the involved pathways and the regulatory mechanisms are not completely understood. In the last few years, there has been a growing interest in the role of microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) in the development of several inflammation-related diseases (Table 1). These noncoding RNAs have emerged as important transcriptional regulators in both physiologic and pathophysiological conditions (19–21). In physiologic homeostasis, these nucleic acids may participate in cell differentiation, proliferation, apoptosis, hematopoiesis, limb morphogenesis, and important metabolic pathways, such as insulin secretion, triglyceride and cholesterol biosynthesis, and oxidative stress (20, 22, 23). Given their fundamental biologic roles, it is not surprising that miRNAs expression is tightly controlled and that its dysregulation can lead to disease onset.

Maternal nutrition during pregnancy and lactation influences offspring development and health. Novel studies have described the effects on next generation obesity-related features depending on maternal macro- and micro-nutrient perinatal feeding. We hypothesized that the maternal obesogenic diet during pregnancy and lactation programs an obese phenotype, while maternal micronutrient supplementation at these stages could partially prevent these features. Thus, the aim was to assess the influence of a perinatal maternal feeding with an obesogenic diet enriched in fat and sucrose and a micronutrient supplementation during pregnancy and lactation on offspring growth and obese phenotypical features during life course. Female Wistar rats were assigned to four dietary groups during pregnancy and lactation: control, control supplemented with micronutrients (choline, betaine, folic acid and vitamin B12 ), high-fat sucrose (HFS) and HFS supplemented. At weaning, the offspring were transferred to a chow diet, and weight and fat mass were measured at weeks 3, 12 and 20. At birth, both male and female offspring from mothers fed the obesogenic diet showed lower body weight (-5 and -6%, respectively), while only female offspring weight decreased by maternal micronutrient supplementation (-5%). During lactation, maternal HFS diet was associated with increased body weight, while micronutrient supplementation protected against body weight gain. Whole body fat mass content increased at weeks 3, 12 and 20 (from 16 to 65%) due to maternal HFS diet. Maternal micronutrient supplementation decreased offspring fat mass content at week 3 (-8%). Male offspring showed higher adiposity than females at weeks 12 and 20. In conclusion, maternal HFS feeding during pregnancy and lactation was associated with a low offspring weight at birth and obese phenotypical features during adult life in a sex- and time-dependent manner. Furthermore, maternal methyl donor supplementation protected against body weight gain in male offspring during lactation and in female offspring also during juvenile period.

Many nutrients are known for a wide range of activities in prevention and alleviation of various diseases. Recently, their potential role in regulating human health through effects on epigenetics has become evident, although specific mechanisms are still unclear. Thus, nutriepigenetics/nutriepigenomics has emerged as a new and promising field in current epigenetics research in the past few years. In particular, polyphenols, as part of the central dynamic interaction between the genome and the environment with specificity at physiological concentrations, are well known to affect mechanisms underlying human health. This review summarizes the effects of dietary compounds on epigenetic mechanisms in the regulation of gene expression including expression of enzymes and other molecules responsible for drug absorption, distribution, metabolism and excretion in cancer, metabolic syndrome, neurodegenerative disorders and hormonal dysfunction.

This study was conducted to determine the mechanisms implicated in the beneficial effects of apple polyphenols (APs) against diet-induced obesity in Wistar rats, described in a previous study from our group. Supplementation of high-fat sucrose diet with AP prevented adiposity increase by inhibition of adipocyte hypertrophy. Rats supplemented with AP exhibited improved glucose tolerance while adipocytes isolated from these rats showed an enhanced lipolytic response to isoproterenol. AP intake led to reduced Lep, Plin, and sterol regulatory element binding transcription factor 1 (Srebf1) mRNA levels and increased aquaporin 7 (Aqp7), adipocyte enhancer binding protein 1 (Aebp1), and peroxisome proliferator-activated receptor gamma co-activator 1 alpha (Ppargc1a) mRNA levels in epididymal adipocytes. In addition, we found different methylation patterns of Aqp7, Lep, Ppargc1a, and Srebf1 promoters in adipocytes from apple-supplemented rats compared to high-fat sucrose fed rats. The administration of AP protects against body weight gain and fat deposition and improves glucose tolerance in rats. We propose that AP exerts the antiobesity effects through the regulation of genes involved in adipogenesis, lipolysis, and fatty acid oxidation, in a process that could be mediated in part by epigenetic mechanisms.

BACKGROUND: Polyphenols have been reported to prevent chronic diseases such as cardiovascular diseases, cancers, diabetes and neurodegenerative diseases. The objective of the study was to conduct a screening for potential anti-obesity polyphenolic plant extracts using a diet-induced animal model. Rats were fed a high-fat-sucrose (HFS) diet with or without supplementation of different polyphenolic plant extracts (almond, apple, cinnamon, orange blossom, hamamelis, lime blossom, grape vine, and birch) for 56 – 64 days. RESULTS: Body weight gain was lower in rats supplemented with apple, cinnamon, hamamelis and birch extracts as compared to HFS non-supplemented group. Moreover, apple and cinnamon extracts prevented the increase in fat mass promoted by the HFS diet. Insulin resistance, estimated by the homostatic model assessment – insulin resistance (HOMA-IR) index, was reduced in rats fed apple, cinnamon, hamamelis and birch extracts. Apple extract also prevented the HFS-induced hyperglycaemia and hyperleptinaemia. CONCLUSION: Only apple and cinnamon extracts were finally considered as potentially important anti-obesogenic extracts, due to their body fat-lowering effects, while the improvement of obesity-related metabolic complications by apple polyphenols highlights this extract as a promising functional food ingredient for the management of obesity and its metabolic complications. c � 2012 Society of Chemical Industry Supporting information may be found in the online version of this article.

Scope: Increased adiposity is related with monocyte infiltration into the adipose tissue that accentuates inflammation. Antioxidant treatments emerge as approaches to counteract this phenomenon. Methods and results: Cocultures of differentiated 3T3-L1 adipocytes and RAW264.7 macrophages were incubated for 24–72 h with/without 100 nM insulin and/or 200 μM vitamin C (VC). Nitric oxide (NO) secretion (24 h) was measured. Also, expression (24 h) and secretion (72 h) of MCP-1, leptin and apelin were analyzed. NO secretion was significantly inhibited by insulin and VC only in cocultures. MCP-1 expression/secretion was enhanced in cocultures. Insulin incubation reduced MCP-1 expression in both cultures and VC only in controls. Both treatments inhibited MCP-1 secretion in cocultures. Apelin gene expression was induced in cocultures. Insulin induced apelin mRNA expression, but VC inhibited its expression in cocultures under insulin treatment. Apelin secretion was notably induced by insulin and inhibited by VC in cocultures. Leptin expression was decreased in coculture, while presented no effects by VC. Conclusion: VC importantly modulates the established pro-inflammatory state in the interaction between adipocytes and macrophages.

Epigenetics could help to explain individual differences in weight loss after an energy-restriction intervention. Here, we identify novel potential epigenetic biomarkers of weight loss, comparing DNA methylation patterns of high and low responders to a hypocaloric diet. Twenty-five overweight or obese men participated in an 8-wk caloric restriction intervention. DNA was isolated from peripheral blood mononuclear cells and treated with bisulfite. The basal and endpoint epigenetic differences between high and low responders were analyzed by methylation microarray, which was also useful in comparing epigenetic changes due to the nutrition intervention. Subsequently, MALDI-TOF mass spectrometry was used to validate several relevant CpGs and the surrounding regions. DNA methylation levels in several CpGs located in the ATP10A and CD44 genes showed statistical baseline differences depending on the weight-loss outcome. At the treatment endpoint, DNA methylation levels of several CpGs on the WT1 promoter were statistically more methylated in the high than in the low responders. Finally, different CpG sites from WT1 and ATP10A were significantly modified as a result of the intervention. In summary, hypocaloric-diet-induced weight loss in humans could alter DNA methylation status of specific genes. Moreover, baseline DNA methylation patterns may be used as epigenetic markers that could help to predict weight loss.

Summary The objective of the present study was to evaluate the influence of raw and extruded kidney bean (Phaseolus vulgaris L. var. Pinto) consumption on the gut physiology of young growing rats. The intestinal enzyme activity (sucrase, maltase, Na+/K+ ATPase, aminopeptidase N, dipeptidylpeptidase IV, alkaline phosphatase) and the uptake of sugar (d-galactose) and amino acids (l-leucine) were measured in brush border membrane vesicles. Five groups of growing male Wistar rats were fed ad libitum for 15 days on five different 10% protein diets: one containing casein as the main source of protein (Control, C), and four containing raw (RKB1, RKB6) or extruded kidney bean (EKB1, EKB6) at 1% and 6% of total protein content respectively. Extrusion treatment significantly reduced the content of bioactive factors (phytates, tannins) and abolished lectins, trypsin, chymotrypsin, and α-amylase inhibitory activities. Rats fed raw beans (especially RKB6) showed lower growth rate and food intake as compared to those fed extruded legumes, probably due to the high levels of lectins and other anti-nutritive factors in the raw beans. Gut enzymatic activities and uptake of d-galactose and l-leucine were lower in RKB6 and RKB1-fed animals, although they significantly improved in the groups fed extruded beans. Enzymatic activity and uptake in EKB1 were similar to those of casein-fed rats, whereas the uptake and growth rate of EKB6 were different to the control. This is attributable to the higher non-thermolabile biofactor content in the EKB6 diet, especially phytates and tannins, than in EKB1. This article shows the dose-dependent toxicological effects of bioactive factors contained in kidney beans on gut function. The extrusion process reduced their adverse impact on gut physiology and growth rate.

BACKGROUND Oxidative stress plays a role in prostate cancer (PrCa) initiation and development. Selenoprotein-P (SepP; a protein involved in antioxidant defence) mRNA levels are down-regulated in PrCa. The main goal of our study was to assess whether SepP protects prostate cells from reactive oxygen species (ROS) in prostate carcinogenesis. METHODS Modification of SepP levels and ROS conditions in C3(1)/Tag-derived cell lines representing prostate epithelial neoplasia (PIN) lesions (Pr-111, with high SepP expression); and invasive tumors (Pr-14, with very low SepP expression). RESULTS Both Pr-111 and Pr-14 cells express ApoER2 (SepP receptor), which suggests that they may uptake SepP. Pr-14 cells had much higher ROS levels than Pr-111 cells and were highly sensitive to H2O2-mediated cytotoxicity. When SepP mRNA levels were knocked down with siRNAs in Pr-111 cells, a significant increase in ROS and cell growth inhibition upon H2O2 exposure was found. Subsequent administration of purified SepP in the culture medium of these cells was able to rescue the original phenotype. Similarly, administration of SepP to Pr-14 cells was able to reduce ROS concentrations. Administration of flutamide decreased SepP mRNA levels whereas dihydrotestosterone or synthetic androgens induced SepP expression, indicating the importance of androgens for SepP expression. Immunohistochemical analysis using a PrCa tissue microarray further revealed that SepP protein was reduced in 60.8% prostate tumors compared to benign prostates. CONCLUSIONS Levels of SepP in prostate cells determine basal ROS levels and sensitivity to H2O2-induced cytotoxicity. Deregulation of SepP during prostate carcinogenesis may increase free radicals, thus promoting tumor development and de-differentiation. Prostate 71:824–834, 2011. © 2010 Wiley-Liss, Inc.

Proanthocyanidins, also named condensed tannins, are the result of flavanols condensation. Oligomers and polymers of proanthocyanidins can widely be found in the plant kingdom, as in fruits and berries, seeds, flowers, and leaves. They have a putative role as antioxidants, and they affect the inflammatory process via calcium-dependent release of nitric oxide and protect against H(2)O(2)-induced lipid peroxidation. They also demonstrated a role in cardiovascular diseases via vessel relaxation and LDL oxidation inhibition. These condensed tannins have also shown activities that improve diabetic complications, such as neuropathy, retinopathy, or nephropathy, including a decrease in serum glucose and advanced glycation end products. Furthermore, proanthocyanidins have evidenced anticancer properties by mitigating tumor development through induction of apoptosis or inhibition of cell proliferation. Finally, they are able to produce antiadhesive actions against bacteria in urinary and dental infections, including Escherichia coli and Streptococcus mutans. Hence, proanthocyanidins are considered as beneficial molecules in preventing or treating many diseases and pathological conditions. Therefore, finding out more about condensed tannins bioavailability, and understanding the regulatory genes and pathways involved in their effects should be aimed in future research.

We studied the effect of high-fat diet on the expression and activation of the three caveolins in rat skeletal muscle and their association with the insulin signalling cascade. Initial response was characterized by increased signalling through Cav-1 and Cav-3 phosphorylation, suggesting that both participate in an initial acute response to the calorie surplus. Afterwards, Cav-1 signalling was slightly reduced, whereas Cav-3 remained active. Late chronic phase signalling through both proteins was impaired inducing a prediabetic state. Summarizing, caveolins seem to mediate a time-dependent regulation of insulin cascade in response to high-fat diet in muscle.

Aim: To analyse the effects of vitamin C (VC), a potent dietary antioxidant, oral supplementation on body weight gain, behavioural activity, lipolytic response and glucocorticoid metabolism in the early stages of diet-induced overweight in rats. Methods: Food intake, locomotive activity and faecal corticosterone were assessed during the 14 day trial period. After 2 weeks, the animals were sacrificed and the body composition, biochemical markers and lipolytic response from isolated adipocytes from retroperitoneal white adipose tissue were examined. Results: The intake of a high-fat diet by rats induced a significant increase in body weight, adiposity and insulin resistance markers as well as a decrease in faecal corticosterone levels compared with standard diet-fed rats. Interestingly, the animals fed on the cafeteria diet showed a significant increase in the isoproterenol-induced lipolytic response in isolated adipocytes. Furthermore, this cafeteria-fed group showed a reduced locomotive behaviour than the control rats. On the other hand, oral VC supplementation in animals receiving the high-fat diet restored the cafeteria diet effect in some of the analysed variables such as final body weight and plasma insulin to control group levels. Remarkably, increases in locomotive behaviour and a significant decrease in the lipolytic response induced by isoproterenol on isolated adipocytes from animals treated with VC were observed. Conclusion: This work demonstrates that an oral ascorbic acid supplementation has direct effects on behavioural activity and on adipocyte lipolysis in early obesity stages in rats, which could indicate a protective short-term role of this vitamin against adiposity induced by chronic high-fat diet consumption.

Objective The objective of the present study was to determine a possible depot-specific effect of insulin-stimulation on adiponectin gene expression in adipose tissue (AT) explants from subcutaneous and visceral AT. A secondary aim was to analyse the associations of adiponectin plasma levels, as well as control and insulin-stimulated gene expression levels with different features of the metabolic syndrome. Design Visceral and subcutaneous AT biopsies were obtained from 20 subjects (10 men and 10 women) with morbid obesity. Metabolic syndrome and other clinical features were studied. Adiponectin expression from isolated adipocytes was measured both in control and after insulin-stimulation conditions by quantitative PCR. Results Subcutaneous adipocytes expressed significantly higher amounts of adiponectin mRNA than visceral tissue (P = 0.027). Insulin increased adiponectin expression specifically in the omental tissue (P = 0.011). In these patients, waist : hip ratio was directly correlated with adiponectin expression in the visceral depot (r = 0.660; P = 0.014), while fasting glucose levels were inversely associated with adiponectin mRNA in the subcutaneous tissue (r =-0.604; P = 0.022). Adiponectin expression after addition of insulin was positively correlated with some metabolic risk factors (cholesterol, LDL-cholesterol, insulin, C-peptide). Interestingly, local insulin induced an up-regulation of adiponectin expression in the AT of those patients with higher metabolic syndrome disturbances. Conclusions Our results clearly demonstrate that insulin exerts a stimulating effect on adiponectin gene expression in a depot-specific manner. The AT response to insulin stimulus depends on the physiopathological situation, being higher in those individuals with impaired insulin-sensitivity and lipid metabolism.

MILAGRO, FERMIN I., JAVIER CAMPION, AND J. ALFREDO MARTINEZ. Weight gain induced by high-fat feeding involves increased liver oxidative stress. Obesity. 2006;14:1118 -1123. Objective: To assess the effects of high-fat feeding on white adipose tissue gene expression and liver oxidative stress. Research Methods and Procedures: Male Wistar rats were fed on standard pelleted or high-fat diet to produce a diet- induced obesity model. Therefore, body composition, serum biochemical values and liver malondialdehyde (MDA) were determined after 56 days of feeding. Expression (mRNA) values of three genes were also determined by reverse transcriptase-polymerase chain reaction in white adipose tissue. Results: Animals fed on the high-fat diet showed more body weight, higher fat deposition and total liver weight, and increased energy intake compared with those on the stan- dard-fat diet. Serum fasting measurements (glucose, insulin, leptin) and homeostasis model assessment insulin resistance index were significantly increased by the high-fat diet con- sumption. As an indicator of oxidative stress, peroxide decomposition in liver was analyzed, showing an increase of MDA concentrations in rats fed on high-fat diet in comparison with control rats. Interestingly, liver MDA lev- els correlated positively with body weight gain, serum lep- tin, and homeostasis model assessment. Finally, leptin and glycerol-3-phosphate dehydrogenase mRNA levels, but not fatty acid synthase, were increased by high-fat diet in com- parison with the control-fed group. Discussion: These results show a link among increased fat depots, insulin resistance, and liver oxidative stress. Thus, liver oxidative stress probably contributes to hepatic disor- ders and aggravates the metabolic syndrome, which is ac- companied by a stimulation of the esterification of fatty acids as measured by glycerol-3-phosphate dehydrogenase in the adipose tissue, providing support to the hypothesis that not only calories count in the induction of weight gain or metabolic syndrome and that other factors such as oxi- dative stress may be involved.

Summary Aim: Previous studies have reported that β3-adrenergic agonists reduce plasma glucose levels in situations of hyperglycaemia and diabetes in rodents. Nevertheless, the mechanisms still remain unclear. In this context Trecadrine®, a novel compound with affinity for β3-adrenergic receptors, has been tested in alloxan-diabetic rats for its potential use as an anti-diabetic drug, but also to elucidate the role of muscle/liver glucose utilization in the process. Methods and results: Daily oral administration (1 mg/kg) to alloxan-diabetic Wistar rats (n = 10) for 4 days caused a significant reduction in plasma glucose levels (from 15.0 to 8.3 mmol/l) with no apparent effects on insulin secretion. Furthermore, Trecadrine® administration tended to normalize glucose storage (estimated by measuring glucokinase activity) and output (by measuring glucose-6-phosphatase activity) in the liver of diabetic animals. On the other hand, Trecadrine® administration for 4 days resulted in an increase in GLUT1 gene expression in gastrocnemius muscle as compared to insulin-dependent glucose transporter GLUT4. Furthermore, a significant stimulation of 2-deoxy- d-glucose uptake in extensor digitorum longus muscle and, in a lesser degree, in gastrocnemius, but not in soleus muscle and in white adipose tissue, occurs. Conclusions: Trecadrine® reduces glucose output from the liver, thus thus contributing to the reduction of plasma glucose levels to achieve the values of control rats. Furthermore, Trecadrine® administration stimulates glucose uptake in skeletal muscle, especially in those muscles with predominant glycolytic fast-twitched fibres, apparently by a direct non-insulin-dependent mechanism, involving a relative increase in the content of GLUT1 in the plasma membrane as compared with GLUT4. In conclusion, Trecadrine® shows a potent hypoglycaemic effect in the alloxan-induced model of diabetes in rats by decreasing hepatic glucose output and improving muscle glucose uptake.