Alessandra Gambero

Antiobesity effects of yerba maté extract (Ilex paraguariensis) in high-fat diet-induced obese mice.

Because the potential of yerba maté (Ilex paraguariensis) has been suggested in the management of obesity, the aim of the present study was to evaluate the effects of yerba maté extract on weight loss, obesity‐related biochemical parameters, and the regulation of adipose tissue gene expression in high‐fat diet–induced obesity in mice. Thirty animals were randomly assigned to three groups. The mice were introduced to standard or high‐fat diets. After 12 weeks on a high‐fat diet, mice were randomly assigned according to the treatment (water or yerba maté extract 1.0 g/kg). After treatment intervention, plasma concentrations of total cholesterol, high‐density lipoprotein cholesterol, triglyceride, low‐density lipoprotein (LDL) cholesterol, and glucose were evaluated. Adipose tissue was examined to determine the mRNA levels of several genes such as tumor necrosis factor‐α (TNF‐α), leptin, interleukin‐6 (IL‐6), C‐C motif chemokine ligand‐2 (CCL2), CCL receptor‐2 (CCR2), angiotensinogen, plasminogen activator inhibitor‐1 (PAI‐1), adiponectin, resistin, peroxisome proliferator‐activated receptor‐γ2 (PPAR‐γ2), uncoupling protein‐1 (UCP1), and PPAR‐γ coactivator‐1α (PGC‐1α). The F4/80 levels were determined by immunoblotting. We found that obese mice treated with yerba maté exhibited marked attenuation of weight gain, adiposity, a decrease in epididymal fat‐pad weight, and restoration of the serum levels of cholesterol, triglycerides, LDL cholesterol, and glucose. The gene and protein expression levels were directly regulated by the high‐fat diet. After treatment with yerba maté extract, we observed a recovery of the expression levels. In conclusion, our data show that yerba maté extract has potent antiobesity activity in vivo. Additionally, we observed that the treatment had a modulatory effect on the expression of several genes related to obesity.

Interleukin-10 is a protective factor against diet-induced insulin resistance in liver☆

BACKGROUND/AIMS The anti-inflammatory cytokine, interleukin-10 (IL-10), is known to exert a protective role in hepatic damage caused by viruses, alcohol, autoimmunity and a number of experimental aggressors. Recently, a protective role for IL-10 has also been proposed in diet-induced hepatic dysfunction. However, studies about the mechanisms involved in this process are controversial. The objective of this study was to evaluate the role of endogenous IL-10 in the development of hepatic insulin resistance, associated with diet-induced fatty liver disease. METHODS Male Swiss mice treated for eight weeks with a high-fat diet became diabetic and developed non-alcoholic fatty liver disease, which is characterized by increased hepatic fat deposition and liver infiltration by F4/80 positive cells. This was accompanied by an increased hepatic expression of TNF-alpha, IL-6, IL-1beta and IL-10, and by an impaired insulin signal transduction through the insulin receptor/IRS1-IRS2/PI3-kinase/Akt/FOXO1 signaling pathway. RESULTS Upon endogenous IL-10 inhibition for 5 days, using two distinct methods, a neutralizing anti-IL-10 antibody and an antisense oligonucleotide against IL-10, increased hepatic expression of the inflammatory markers TNF-alpha, IL-6, IL-1beta and F4/80 was observed. This was accompanied by a significant negative modulation of insulin signal transduction through insulin receptor/IRS1-IRS2/PI3-kinase/Akt/FOXO1, and by the stimulation of hepatic signaling proteins involved in gluconeogenesis and lipid synthesis. CONCLUSIONS Thus, in an animal model of diet-induced fatty liver disease, the inhibition of IL-10 promotes the increased expression of inflammatory cytokines, the worsening of insulin signaling and the activation of gluconeogenic and lipidogenic pathways.

Maté tea inhibits in vitro pancreatic lipase activity and has hypolipidemic effect on high-fat diet-induced obese mice.

The inhibitory effects of maté tea (MT), a beverage produced with leaves from Ilex paraguariensis, in vitro lipase activity and on obesity in obese mice models were examined. For the in vitro experiment, porcine and human pancreatic lipase (PL) activities were determined by measuring the rate of release of oleic acid from hydrolysis of olive oil emulsified with taurocholate, phospholipids, gum arabic, or polyvinyl alcohol. For the in vivo experiments, animals were fed with a standard diet (SD, n = 10) or high‐fat diet (HFD, n = 30) for 16 weeks. After the first 8 weeks on the HFD, the animals were treated with 1 and 2 g/kg of body weight of MT. The time course of the body weight and obesity‐related biochemical parameters were evaluated. The results showed that MT inhibited both porcine and human PL (half‐maximal inhibitory concentration = 1.5 mg MT/ml) and induced a strong inhibition of the porcine lipase activity in the hydrolysis of substrate emulsified with taurocholate + phosphatidylcholine (PC) (83 ± 3.8%) or PC alone (62 ± 4.3%). MT suppressed the increases in body weight (P < 0.05) and decreased the serum triglycerides and low‐density lipoprotein (LDL)‐cholesterol concentrations at both doses (from 190.3 ± 5.7 to 135.0 ± 8.9 mg/dl, from 189.1 ± 7.3 to 129.3 ± 17.6 mg/dl; P < 0.05, respectively) after they had been increased by the HFD. The liver lipid content was also decreased by the diet containing MT (from 132.6 ± 3.9 to 95.6 ± 6.1 mg/g of tissue; P < 0.05). These results suggest that MT could be a potentially therapeutic alternative in the treatment of obesity caused by a HFD.

Anti-inflammatory effects of yerba mate extract (Ilex paraguariensis) ameliorate insulin resistance in mice with high fat diet-induced obesity

The aim of the present study was to evaluate the effects of yerba maté extract upon markers of insulin resistance and inflammatory markers in mice with high fat diet-induced obesity. The mice were introduced to either standard or high fat diets. After 12 weeks on a high fat diet, mice were randomly assigned to one of the two treatment conditions, water or yerba maté extract at 1.0 gkg(-1). After treatment, glucose blood level and hepatic and soleus muscle insulin response were evaluated. Serum levels of TNF-α and IL-6 were evaluated by ELISA, liver tissue was examined to determine the mRNA levels of TNF-α, IL-6 and iNOS, and the nuclear translocation of NF-κB was determined by an electrophoretic mobility shift assay. Our data show improvements in both the basal glucose blood levels and in the response to insulin administration in the treated animals. The molecular analysis of insulin signalling revealed a restoration of hepatic and muscle insulin substrate receptor (IRS)-1 and AKT phosphorylation. Our data show that the high fat diet caused an up-regulation of the TNF-α, IL-6, and iNOS genes. Although after intervention with yerba maté extract the expression levels of those genes returned to baseline through the NF-κB pathway, these results could also be secondary to the weight loss observed. In conclusion, our results indicate that yerba maté has a potential anti-inflammatory effect. Additionally, these data demonstrate that yerba maté inhibits hepatic and muscle TNF-α and restores hepatic insulin signalling in mice with high fat diet-induced obesity.

Mesenteric adipose tissue alterations resulting from experimental reactivated colitis.

Background: Adipose tissue secretes a large number of hormones that act either locally or at distant sites, modulating immune responses, inflammation, and many endocrine and metabolic functions. Abnormalities of fat in the mesentery have been long recognized in surgical specimens as characteristic features of Crohns disease; however, the importance of this in chronic inflammatory disease is unknown. Additionally, adipocytes in depots that enclose lymph nodes or other dense masses of lymphoid tissue have many site‐specific physiological properties. Methods: In this study, the alterations of mesenteric and perinodal mesenteric adipose tissue during experimental colitis, induced by repeated intracolonic trinitrobenzene sulfonic acid instillations, were evaluated, focusing on morphological and activity alterations and the adipocytokine production profile. Results: After a 35‐day protocol, the colitis animals presented greater mesenteric fat masses despite their lower body weights. Another adipose tissue depot, epididymal adipose tissue, was also evaluated and no change in mass was observed. The mesenteric adipocyte from colitis animals had a reduced diameter, normal PPAR‐&ggr;‐2 expression, and higher basal lipolysis and TNF‐&agr; production when compared to normal rats. Perinodal mesenteric adipocytes present normal diameters, downregulated levels of PPAR‐&ggr;‐2, higher basal lipolysis and TNF‐&agr;, and leptin and adiponectin production. Conclusions: The findings suggest that mesenteric adipose tissue has a site‐specific response during experimental inflammation, where perinodal adipose tissue retains the ability to produce different adipocytokines. These substances may interfere in many lymph node aspects, while mesenteric adipose tissue produces substances that could contribute directly to aggravate the inflammatory process.

The importance of oxygen free radicals in the etiopathogenesis of diversion colitis in rats.

PURPOSE Quantify the levels of oxidative DNA damage of epithelial colon cells comparing segments with and without fecal stream. METHODS Sixty Wistar rats were subjected to deviation of fecal stream by proximal colostomy and a distal mucosal fistula. Animals were divided into three experimental groups that were sacrificed 6, 12 and 24 weeks after surgery. In each experimental group, five animals underwent laparotomy without intestinal deviation (sham subgroup). The diagnosis of colitis was made by histopathological analysis and the inflammatory activity index by graduated scale. The neutrophil infiltration was determined by myeloperoxidase tissue levels and the intensity of oxidative DNA damage by comet assay. The Mann-Withney and Student t test were used to compare the results among experimental subgroups and the Kruskal-Wallis test for variance analysis, adopting a significance level of 5% (p<0.05). RESULTS Colon segments without fecal stream was shown higher histological inflammatory score of the colon wall after 12 and 24 weeks (p=0.001) that increased with the time of diversion (p=0.01). The activity of myeloperoxidase in segments without fecal stream decreased with the time (p=0.001). Oxidative DNA damage levels were significantly higher in the segments without fecal stream, (p=0.0001), independent of time of colon diversion, and increase with the time (p=0.0007). CONCLUSIONS Colon segments without fecal stream showed high levels of oxidative DNA damage related to histological alterations observed in diversion colitis. The levels of oxidative DNA damage in segments devoid of the fecal stream increase with the time of intestinal exclusion.

Attenuation of colitis injury in rats using Garcinia cambogia extract

Inflammatory bowel disease (IBD), Crohns disease and ulcerative colitis are chronic enteropathies that probably result from a dysregulated mucosal immune response. These pathologies are characterized by oxidative and nitrosative stress, leukocyte infiltration and up‐regulation of pro‐inflammatory substances. Current IBD treatment presents limitations in both efficacy and safety that stimulated the search for new active compounds. Garcinia cambogia extract has attracted interest due to its pharmacological properties, including gastroprotective effects. In this study, the antiinflammatory activity of a garcinia extract was assessed in TNBS‐induced colitis rats. The results obtained revealed that garcinia administration to colitic rats significantly improved the macroscopic damage and caused substantial reductions in increases in MPO activity, COX‐2 and iNOS expression. In addition, garcinia extract treatment was able to reduce PGE2 and IL‐1β colonic levels. These antiinflammatory actions could be related to a reduction in DNA damage in isolated colonocytes, observed with the comet assay. Finally, garcinia extract caused neither mortality nor toxicity signals after oral administration. As such, the antiinflammatory effects provided by the Garcinia cambogia extract result in an improvement of several parameters analysed in experimental colitis and could provide a source for the search for new antiinflammatory compounds useful in IBD treatment. Copyright

The in vitro and in vivo effects of yerba mate (Ilex paraguariensis) extract on adipogenesis

The aim of this study was to evaluate the effects of yerba mate extract and its principal bioactive compounds on adipogenesis. The anti-adipogenic effects of yerba mate, chlorogenic acid, quercetin and rutin were evaluated in 3T3-L1 cells using a PCR array. The results obtained in vitro were validated in vivo in a high-fat diet-induced model of obesity. The in vitro and in vivo results demonstrated that yerba mate extract down-regulated the expression of genes that regulate adipogenesis, such as Creb-1and C/EBPα, and the extract up-regulated the expression of genes related to the inhibition of adipogenesis, including Dlk1, Gata2, Gata3, Klf2, Lrp5, Pparγ2, Sfrp1, Tcf7l2, Wnt10b, and Wnt3a. In summary, it was demonstrated that yerba mate and its bioactive compounds regulate the expression of genes related to in vitro adipogenesis. Furthermore, yerba mate might regulate adipogenesis through the Wnt pathway.

The inhibitory effects of H + K + ATPase inhibitors on human neutrophils in vitro: Restoration by a K + ionophore

Abstract.Objective:This study investigated the ability of proton pump inhibitors (PPI), such as omeprazole and pantoprazole, to inhibit neutrophil migration, calcium mobilization and the mechanisms involved in this inhibition.Methods:Neutrophils were incubated with different concentrations of omeprazole and pantoprazole for 30 min and stimulated to migrate with fMLP and IL-8. Treatment toxicity was assessed by MTT assay. The intracellular calcium levels were analyzed in neutrophils pre-treated with omeprazole and pre-loaded with FURA-2AM, when stimulated with fMLP. The activity of p38 MAP Kinase was evaluated by Western blot after treatment with omeprazole.Results:Omeprazole is able to inhibit neutrophil chemotaxis to fMLP and IL-8. Pantoprazole demonstrated the same ability. This inhibitory effect was not due to a toxic effect of the proton pump inhibitors. Inhibition of v-ATPase by bafilomycin did not modify the ability of fMLP or IL-8 to induce neutrophil migration. Omeprazole was also able to decrease intracellular calcium availability. The addition of a potassium ionophore, nigericin, restored the migratory ability, as well as the intracellular calcium levels. The activity of p38 MAP Kinase was decreased in neutrophils pretreated with omeprazole.Conclusion:Proton pump inhibitors promote inhibition of H+K+ATPase in neutrophils, resulting in cationic flow disturbances through the cellular membrane that, consequently, inhibit migratory and intracellular events such as calcium influx and p38 MAP Kinase activation.

Nitric oxide has a role in regulating VLA-4-integrin expression on the human neutrophil cell surface.

Recent research demonstrates that the beta1 integrins may be involved in neutrophil migration. Here, we investigate the role of nitric oxide in the expression and function of the very late antigen-4 (VLA-4) and Mac-1 integrins on human neutrophils. Human blood neutrophils were treated with N(omega)-nitro-L-arginine methyl ester (L-NAME) and their adhesion to fibronectin (FN) and serum observed. Adhesion of neutrophils to FN and serum increased significantly following incubation with 0.1mM L-NAME by 65.5 and 44.6%, respectively. Increased adhesions to FN and serum were abolished by a VLA-4-specific monoclonal antibody, HP2/1, and a Mac-1-specific monoclonal antibody, ICRF 44, respectively. The microfilament- and microtubule-depolymerizing agents, dihydrochalasin B and nocodazole, were also able to reverse L-NAME-induced adhesion to both FN and serum. L-NAME induced a discrete increase in the expression of CD49d (VLA-4, 25.3+/-4.8%), but not CD11b, on the neutrophil cell surface, as detected by flow cytometry. Results indicate that NO has a role in regulating VLA-4 and Mac-1 function on the human neutrophil cell surface and that this modulation in integrin function is accompanied by cytoskeletal rearrangements and changes in the ability of the neutrophil to adhere to the extracellular matrix.