Low ethanol consumption induces enhancement of insulin sensitivity in liver of normal rats

Moderate amounts of alcohol intake have been reported to have a protective effect on the cardiovascular system and this may involve enhanced insulin sensitivity. We established an animal model of increased insulin sensitivity by low ethanol consumption and here we investigated metabolic parameters and molecular mechanisms potentially involved in this phenomenon. For that, Wistar rats have received drinking water either without (control) or with 3% ethanol for four weeks. The effect of ethanol intake on insulin sensitivity was analyzed by insulin resistance index (HOMA-IR), intravenous insulin tolerance test (IVITT) and lipid profile. The role of liver was investigated by the analysis of insulin signaling pathway, GLUT2 gene expression and tissue glycogen content. Rats consuming 3% ethanol showed lower values of HOMA-IR and plasma free fatty acids (FFA) levels and higher hepatic glycogen content and glucose disappearance constant during the IVITT. Neither the phosphorylation of insulin receptor (IR) and insulin receptor substrate-1 (IRS-1), nor its association with phosphatidylinositol-3-kinase (PI3-kinase), was affected by ethanol. However, ethanol consumption enhanced liver IRS-2 and protein kinase B (Akt) phosphorylation (3 times, P < 0.05), which can be involved in the 2-fold increased (P < 0.05) hepatic glycogen content. The GLUT2 protein content was unchanged. Our findings point out that liver plays a role in enhanced insulin sensitivity induced by low ethanol consumption. © 2005 Elsevier Inc. All rights reserved.

Utilization of neuromuscular electrical stimulation in the acute phase of ankle immobilization at 90°: Study in rats

Objective: To evaluate the skeletal muscle glycogen content and plasmatic concentration of interleukin -6 (IL-6), interleukin-4 (IL-4), interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-α) in rats submitted to electrical stimulation sessions during the first three days of ankle immobilization at the position of 90°. Methods: Albinomale Wistar rats(3-4 months) were maintained in vivarium. conditions with food and water ad libitum, Submitted to 12 h photoperiodic cycles of light/dark, and distributed into 7 experimental groups (n = 6): control(C), immobilized 1 day(I1) immobilized 1 day and electrically stimulated(IE1) immobilized 2 days(12), immobilized 2 days and electrically stimulated(IE2), immobilized 3 days(13) and immobilized 3 days and electrically stimulated(IE3). Groups I utilized an acrylic resin orthesis model and groups electrically stimulated (IE) utilized the orthesis and a session of electrotherapy by a Dualpex 961 (biphasic quadratic pulse, 10 Hz, 0.4 ms, 5.0 mA, one 20 min session a day). After the experimental period, the rats were anesthetized with pentobarbital sodium(40 mg/kg) and a blood sample was colleted to evaluate the plasmatic concentration of interleukins by means of the radioimmunoassay method. The soleus and the white portion of the gastrocnemius muscle were colleted for glycogen reserves analysis(GLY). Other groups of rats were used to apply the glucose tolerance test(GTT) and insulin tolerance test(ITT). For statistical analysis, the Kolmogorov-Smirnov normality test followed by ANOVA and the Tukey tests were utilized, with a critical level established at 5%. Results: In ITT test, groups IE enhanced the skeletal muscle glucose uptake, but no changes were observed in GTT after the therapy session, which indicates that electrical stimulation is a sensibilizing method to augment skeletal muscle glucose uptake. The GLY reserves were reduced in I groups, which indicate that disuse altered insulin sensitivity and compromised energetic homeostasis. However. the IE groups displayed an augment in GLY content, suggesting that electrical stimulation restores the enzymatic pathways altered by immobilization. The improvement in GLY was accompanied by an elevation of the plasmatic concentration of IL-6 and TNF-α, showing the participation of these interleukins in the control of metabolic profile. Plasmatic concentrations of IL-10 were elevated only after 3 days of IE while IL-4 did not display any modifications. Conclusion: The results suggest that neuromuscular electricaf stimulation is an important toot in the maintenance of energetic, conditions of musculature submitted to immobilization, and presents multifactor mechanisms linked to interleukins action that converge to maintain the energetic equilibrium of the tissue in disuse.

Modulation of insulin secretion by physical training during recovery from protein malnutrition in rats

Objective: The purpose of the present study was to examine insulin secretion in rats submitted to protein restriction and nutritional recovery associated or not to physical training. Methods: The experiment was designed in two sets of five weeks each. In the first set the rats were fed a nonnal-protein diet(17%-control group) or a low-protein diet (6%-malnourished group) for five weeks. After this, all animals were fed the 17% protein diet and separated into four groups: sedentary control(SC); trained eontrol(TC); sedentary recovered(SR) and trained recovered(TR). TC and TR rats performed swimming exercise. Results: The results indicated efficiency of the 6% protein diet in producing signs of malnutrition, as reduction in body weight gain and serum albumin levels, as well as liver fat. Serum insulin in the fed state and insulin secretion by isolated pancreatic islets in response to glucose were Keduced,but peripheral sensitivity to insulin was increased and glucose tolerance was not changed in the protein deficient rats, indicating adaptation to malnutrition. Diet protocol for nutritional recovery was efficient in repairing body weight gain, serum albumin and liver fat levels of the previously malnourished rats. Glucose induced insulin release by pancreatic islets remained low after nutritional recovery. Insulin secretion by the islets isolated from rats submitted to exercise training during nutritional recovery was improved when compared with the sedentary animals. Conclusion: This indicates that exercise training may be useful in the treatment of protein calorie malnutrition, concerning to glucose induced insulip secretion.

Metabolic syndrome signs in Wistar rats submitted to different high-fructose ingestion protocols

In search of an adequate model for the human metabolic syndrome, the metabolic characteristics of Wistar rats were analysed after being submitted to different protocols of high fructose ingestion. First, two adult rat groups (aged 90 d) were studied: a control group (C1; n 6) received regular rodent chow (Labina, Purina) and a fructose group (F1; n 6) was fed on regular rodent chow. Fructose was administered as a 10 % solution in drinking water. Second, two adult rat groups (aged 90 d) were evaluated: a control group (C2; n 6) was fed on a balanced diet (AIN-93G) and a fructose group (F2; n 6) was fed on a purified 60 % fructose diet. Finally, two young rat groups (aged 28 d) were analysed: a control group (C3; n 6) was fed on the AIN-93G diet and a fructose group (F3; n 6) was fed on a 60 % fructose diet. After 4-8 weeks, the animals were evaluated. Glucose tolerance, peripheral insulin sensitivity, blood lipid profile and body fat were analysed. In the fructose groups F2 and F3 glucose tolerance and insulin sensitivity were lower, while triacylglycerolaemia was higher than the respective controls C2 and C3 (P < 0.05). Blood total cholesterol, HDL and LDL as well as body fat showed change only in the second protocol. In conclusion, high fructose intake is more effective at producing the signs of the metabolic syndrome in adult than in young Wistar rats. Additionally, diet seems to be a more effective way of fructose administration than drinking water.

Could albumin level explain the higher mortality in hemodialysis patients with pulmonary hypertension?

Background: The pathogenesis of pulmonary hypertension (PH) in hemodialysis is still unclear. The aim of thisstudy was to identify the risk factors associated with the presence of PH in chronic hemodialysis patients and toverify whether these factors might explain the highest mortality among them.Methods: We conducted a retrospective study of hemodialysis patients who started treatment from August 2001to October 2007 and were followed up until April 2011 in a Brazilian referral medical school. According to theresults of echocardiography examination, patients were allocated in two groups: those with PH and those withoutPH. Clinical parameters, site and type of vascular access, bioimpedance, and laboratorial findings were comparedbetween the groups and a logistic regression model was elaborated. Actuarial survival curves were constructed andhazard risk to death was evaluated by Cox regression analysis.Results: PH > 35 mmHg was found in 23 (30.6%) of the 75 patients studied. The groups differed in extracellularwater, ventricular thickness, left atrium diameter, and ventricular filling. In a univariate analysis, extracellular waterwas associated with PH (relative risk = 1.194; 95% CI of 1.006 1.416; p = 0.042); nevertheless, in a multiple model,only left atrium enlargement was independently associated with PH (relative risk =1.172; 95% CI of 1.010 1.359;p = 0.036). PH (hazard risk = 3.008; 95% CI of 1.285 7.043; p = 0.011) and age (hazard risk of 1.034 per year of age;95% CI of 1.000 7.068; p = 0.047) were significantly associated with mortality in a multiple Cox regression analysis.However, when albumin was taken in account the only statistically significant association was between albuminlevel and mortality (hazard risk = 0.342 per g/dL; 95% CI of 0.119 0.984; p = 0.047) while the presence of PH lost itsstatistical significance (p = 0.184). Mortality was higher in patients with PH (47.8% vs 25%) who also had astatistically worse survival after the sixth year of follow up.Conclusions: PH in hemodialysis patients is associated with parameters of volume overload that sheds light on itspathophysiology. Mortality is higher in hemodialysis patients with PH and the low albumin level can explain thisassociation.© 2012 Greenfield et al.; licensee BioMed Central Ltd.

An optimised electrochemical biosensor for the label-free detection of C-reactive protein in blood

C-reactive protein (CRP) is an acute phase protein whose levels are increased in many disorders. There exists, in particular, a great deal of interest in the correlation between blood serum levels and the severity of risk for cardiovascular disease. A sensitive, label-free, non-amplified and reusable electrochemical impedimetric biosensor for the detection of CRP in blood serum was developed herein based on controlled and coverage optimised antibody immobilization on standard polycrystalline gold electrodes. Charge transfer resistance changes were highly target specific, linear with log. CRP. concentration across a 0.5-50. nM range and associated with a limit of detection of 176. pM. Significantly, the detection limits are better than those of current CRP clinical methods and the assays are potentially cheap, relatively automated, reusable, multiplexed and highly portable. The generated interfaces were capable not only of comfortably quantifying CRP across a clinically relevant range of concentrations but also of doing this in whole blood serum with interfaces that were, subsequently, reusable. The importance of optimising receptor layer resistance in maximising assay sensitivity is also detailed. © 2012.

Pathological and behavioral risk factors for higher serum c-reactive protein concentrations in free-living adults - A Brazilian community-based study

Low-grade chronic systemic inflammation is often associated with chronic non-communicable diseases, and its most frequently used marker, the C-reactive protein (CRP), has become an identifier of such diseases as well as an independent predictor for cardiovascular disorders and mortality. CRP is produced in response to pro-inflammatory signaling and to individual and behavioral factors, leading to pathological states. The aim of this study was to rank the predicting factors of high CRP concentrations in free-living adults from a community-based sample. We evaluated 522 adults (40-84 years old; 381 women) for anthropometric characteristics, dietary intake, clinical and physical tests, and blood analysis. Subjects were assigned to groups, according to CRP concentrations, as normal CRP (G1;<3.0 mg/L; n = 269), high CRP (G2; 3.0-6.0 mg/L; n = 139), and very high CRP (G3; >6.0 mg/dL; n = 116). Statistical comparison between groups used one-way ANOVA or Kruskal-Wallis tests, and prediction of altered values in increasing CRP was evaluated by proportional hazard models (odds ratio). CRP distribution was influenced by gender, body mass index, body and abdominal fatness, blood leukocytes, and neutrophil counts. The higher CRP group was discriminated by the above variables in addition to lower VO2max, serum metabolic syndrome components (triglycerides, glucose, and HDL cholesterol), higher insulin, homeostasis assessment of insulin resistance, uric acid, gamma-GT, and homocysteine. After adjustments, only fatness, blood leukocytes, and hyperglycemia remained as independent predictors for increased serum CRP concentrations. Intervention procedures to treat low-grade chronic inflammation in overweight women would mainly focus on restoring muscle mass and functions in addition to an antioxidant-rich diet. © 2012 Springer Science+Business Media, LLC.

Effect of dialysate sodium reduction on body water volume, blood pressure, and inflammatory markers in hemodialysis patients - A prospective randomized controlled study

Accumulating evidence suggests an association between body volume overload and inflammation in chronic kidney diseases. The purpose of this study was to evaluate the effect of dialysate sodium concentration reduction on extracellular water volume, blood pressure (BP), and inflammatory state in hemodialysis (HD) patients. In this prospective controlled study, adult patients on HD for at least 90 days and those with C-reactive protein (CRP) levels ≥ 0.7 mg/dL were randomly allocated into two groups: group A, which included 29 patients treated with reduction of dialysate sodium concentration from 138 to 135 mEq/L; and group B, which included 23 HD patients not receiving dialysate sodium reduction (controls). Of these, 20 patients in group A and 18 in group B completed the protocol study. Inflammatory, biochemical, hematological, and nutritional markers were assessed at baseline and after 8 and 16 weeks. Baseline characteristics were not significantly different between the two groups. Group A showed a significant reduction in serum concentrations of tumor necrosis factor-α, and interleukin-6 over the study period, while the BP and extracellular water (ECW) did not change. In Group B, there were no changes in serum concentrations of inflammatory markers, BP, and ECW. Dialysate sodium reduction is associated with attenuation of the inflammatory state, without changes in the BP and ECW, suggesting inhibition of a salt-induced inflammatory response. Copyright © 2013 Informa Healthcare USA, Inc.

Previous contact with Strongyloides venezuelensis contributed to prevent insulitis in MLD-STZ diabetes

Epidemiological and experimental studies support the idea that helminth infections can induce a protective effect against the development of autoimmune and allergic diseases. In this study we characterized the immune response induced by Strongyloides venezuelensis infection in C57BL/6 mice and then evaluated the effect of a previous contact with this helminth in the outcome of type 1 diabetes. Animals were initially infected with 2000 L3 larvae from S. venezuelensis and euthanized 22. days later. An acute phase, identified by a high amount of eggs per gram of feces, was established between days 7 and 9 post-infection. Recovery from infection was associated with a Th2 polarized response characterized by a significant level of serum IgG1 specific antibodies and also a significant production of IL-5 and IL-10 by spleen cells stimulated with S. venezuelensis soluble antigen. Immunization with soluble S. venezuelensis antigen associated with complete Freund's adjuvant followed by infection with S. venezuelensis protected mice from diabetes development induced by streptozotocin. Protection was characterized by a higher body weight gain, lower glycemic levels, much less severe insulitis and preserved insulin production. Together, these results indicate that S. venezuelensis contributed to protect C57BL/6 mice against experimental diabetes induced by streptozotocin. © 2013 Elsevier Inc.

The most frequent cardiovascular risk factors in Brazilian aged 80 years or older

To identify the most frequent cardiovascular risk factors (CRFs) in Brazilian participants. Sample of 113 individuals aged 80 to 95 years (83.4 + 2.9 years), of both sexes, from Presidente Prudente, São Paulo state. Waist circumference (WC), body mass index, percentage of total body fat (% BF), hypertension, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides, and glucose were used for characterization of risk factors. The chi-square test was used to assess proportions of risk factors and Student's t test to compare the results between the sexes. High prevalence of risk factor was observed, mainly hypertension (67.3%) and % BF (79.6%). Male participants presented higher weight, height, and WC (p <.001), and female participants, higher TC and % BF (p <.001). Only 7.1% of male and 4.2% of female participants showed no risk factors, and 71.3% of male and 85.9% of female participants had three or more. The participants presented a high prevalence of CRFs, particularly percentage of body fat and hypertension, and, in addition, female participants also presented TC. © The Author(s) 2011.

The relationship between training status, blood pressure and uric acid in adults and elderly

Background: Hypertension can be generated by a great number of mechanisms including elevated uric acid (UA) that contribute to the anion superoxide production. However, physical exercise is recommended to prevent and/or control high blood pressure (BP). The purpose of this study was to investigate the relationship between BP and UA and whether this relationship may be mediated by the functional fitness index.Methods: All participants (n = 123) performed the following tests: indirect maximal oxygen uptake (VO2max), AAHPERD Functional Fitness Battery Test to determine the general fitness functional index (GFFI), systolic and diastolic blood pressure (SBP and DBP), body mass index (BMI) and blood sample collection to evaluate the total-cholesterol (CHOL), LDL-cholesterol (LDL-c), HDL-cholesterol (HDL-c), triglycerides (TG), uric acid (UA), nitrite (NO2) and thiobarbituric acid reactive substances (T-BARS). After the physical, hemodynamic and metabolic evaluations, all participants were allocated into three groups according to their GFFI: G1 (regular), G2 (good) and G3 (very good).Results: Baseline blood pressure was higher in G1 when compared to G3 (+12% and +11%, for SBP and DBP, respectively, p<0.05) and the subjects who had higher values of BP also presented higher values of UA. Although UA was not different among GFFI groups, it presented a significant correlation with GFFI and VO2max. Also, nitrite concentration was elevated in G3 compared to G1 (140±29 μM vs 111± 29 μM, for G3 and G1, respectively, p<0.0001). As far as the lipid profile, participants in G3 presented better values of CHOL and TG when compared to those in G1.Conclusions: Taking together the findings that subjects with higher BP had elevated values of UA and lower values of nitrite, it can be suggested that the relationship between blood pressure and the oxidative stress produced by acid uric may be mediated by training status. © 2013 Trapé et al.; licensee BioMed Central Ltd.

Metabolic profile and genotoxicity in obese rats exposed to cigarette smoke

Objective Experimental studies have shown that exposure to cigarette smoke has negative effects on lipid metabolism and oxidative stress status. Cigarette smoke exposure in nonpregnant and pregnant rats causes significant genotoxicity (DNA damage). However, no previous studies have directly evaluated the effects of obesity or the association between obesity and cigarette smoke exposure on genotoxicity. Therefore, the aim of the present investigation was to evaluate DNA damage levels, oxidative stress status and lipid profiles in obese Wistar rats exposed to cigarette smoke. Design and Methods Female rats subcutaneously (sc) received a monosodium glutamate solution or vehicle (control) during the neonatal period to induce obesity. The rats were randomly distributed into three experimental groups: control, obese exposed to filtered air, and obese exposed to tobacco cigarette smoke. After a 2-month exposure period, the rats were anesthetized and killed to obtain blood samples for genotoxicity, lipid profile, and oxidative stress status analyses. Results The obese rats exposed to tobacco cigarette smoke presented higher DNA damage, triglycerides, total cholesterol, free fatty acids, VLDL-c, HDL-c, and LDL-c levels compared to control and obese rats exposed to filtered air. Both obese groups showed reduced SOD activity. These results showed that cigarette smoke enhanced the effects of obesity. Conclusion In conclusion, the association between obesity and cigarette smoke exposure exacerbated the genotoxicity, negatively impacted the biochemical profile and antioxidant defenses and caused early glucose intolerance. Thus, the changes caused by cigarette smoke exposure can trigger the earlier onset of metabolic disorders associated with obesity, such as diabetes and metabolic syndrome. Copyright © 2012 The Obesity Society.

Efeito do exercício aeróbio sobre os níveis séricos de leptina em mulheres obesas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of protein, carbohydrate, lipid, and selenium levels on the performance, carcass yield, and blood changes in broilers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Low-Level Fluoride Exposure Increases Insulin Sensitivity in Experimental Diabetes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)