Endurance exercise training increases APPL1 expression and improves insulin signaling in the hepatic tissue of diet-induced obese mice, independently of weight loss

Hepatic insulin resistance is the major contributor to fasting hyperglycemia in type 2 diabetes. The protein kinase Akt plays a central role in the suppression of gluconeogenesis involving forkhead box O1 (Foxo1) and peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1a), and in the control of glycogen synthesis involving the glycogen synthase kinase beta (GSK3 beta) in the liver. It has been demonstrated that endosomal adaptor protein APPL1 interacts with Akt and blocks the association of Akt with its endogenous inhibitor, tribbles-related protein 3 (TRB3), improving the action of insulin in the liver. Here, we demonstrated that chronic exercise increased the basal levels and insulin-induced Akt serine phosphorylation in the liver of diet-induced obese mice. Endurance training was able to increase APPL1 expression and the interaction between APPL1 and Akt. Conversely, training reduced both TRB3 expression and TRB3 and Akt association. The positive effects of exercise on insulin action are reinforced by our findings that showed that trained mice presented an increase in Foxo1 phosphorylation and Foxo1/PGC-1a association, which was accompanied by a reduction in gluconeogenic gene expressions (PEPCK and G6Pase). Finally, exercised animals demonstrated increased at basal and insulin-induced GSK3 beta phosphorylation levels and glycogen content at 24?h after the last session of exercise. Our findings demonstrate that exercise increases insulin action, at least in part, through the enhancement of APPL1 and the reduction of TRB3 expression in the liver of obese mice, independently of weight loss. J. Cell. Physiol. 227: 29172926, 2012. (C) 2011 Wiley Periodicals, Inc.

Carbohydrate- and lipid-enriched meals acutely disrupt glycemic homeostasis by inducing transient insulin resistance in rats

Chronic intake of high-carbohydrate or high-lipid diets is a well-known insulin resistance inducer. This study investigates the immediate effect (1-6 h) of a carbohydrate-or lipid-enriched meal on insulin sensitivity. Fasted rats were refed with standard, carbohydrate-enriched (C), or lipid-enriched (L) meal. Plasma insulin, glucose, and non-esterified fatty acids (NEFA) were measured at 1, 2, 4, and 6 h of refeeding. The glucose-insulin index showed that either carbohydrates or lipids decreased insulin sensitivity at 2 h of refeeding. At this time point, insulin tolerance tests (ITTs) and glucose tolerance tests (GTTs) detected insulin resistance in C rats, while GTT confirmed it in L rats. Reduced glycogen and phosphorylated AKT and GSK3 content revealed hepatic insulin resistance in C rats. Reduced glucose uptake in skeletal muscle subjected to the fatty acid concentration that mimics the high NEFA level of L rats suggests insulin resistance in these animals is mainly in muscle. In conclusion, carbohydrate-or lipid-enriched meals acutely disrupt glycemic homeostasis, inducing a transient insulin resistance, which seems to involve liver and skeletal muscle, respectively. Thus, the insulin resistance observed when those types of diets are chronically consumed may be an evolution of repeated episodes of this transient insulin resistance.

Protein diets promote the maturation of oocytes and spawning of Piaractus mesopotamicus kept in cages

The objective of this study was to evaluate the effects of balanced diets on the maturation of oocytes and the reproductive performance of P. mesopotamicus in cages. A completely random design with 224 fish in 16 cages measuring 5 m(3) was employed for this purpose. The treatments consisted of diets containing 18, 24, 30, and 36% crude protein (CP) provided ad libitum. The external and internal morphological characteristics of the specimens were examined, as well as: the position of the germinal vesicle, the distribution of oocyte diameters, the fertilization and hatching rates, the number of oocytes released, the total number of oocytes, the remaining weight and total weight of the ovaries, the gonadosomatic index, the condition factor (K), and the histology of the oocytes and ovaries post-spawning and during ovarian regression. The diameters of the oocytes collected before the first hormonal application displayed a unimodal distribution for the lowest protein content and a polymodal distribution for the other treatments. A similar situation was seen during spawning. The lowest fertilization and hatching rates were found as a consequence of the treatment with 30% CP (P < 0.05). The greatest hatching rate occurred in the females fed 18% CP. The greatest total oocyte weight was found in the specimens that received between 30 and 36% CP. The lowest K index was found in the females fed 36% CP. In conclusion, a diet containing 18% CP satisfies the reproductive requirements of females adapted to this system.

Dynamics of free and H-3-labelled glutamine concentrations during zygotic and somatic embryogenesis of Feijoa [Acca sellowiana (O. Berg.) Burret]

Amino acids play fundamental roles in plant morphogenesis. Among sources of organic nitrogen (N), glutamine has frequently been used during the establishment and maintenance of cell and tissue cultures. The aim of this study was analyse endogenous levels of glutamine during somatic and zygotic embryogenesis of Acca sellowiana (Feijoa or pineapple guava). The in vitro absorption of H-3-labelled glutamine was investigated. Zygotic embryos and embryogenic cultures (EC) were evaluated at 30 d and 70 d after explant inoculation onto the medium. Endogenous levels of glutamine were similar during zygotic and somatic embryogenesis, and showed a gradual decline until day-24 in culture. The highest rates of H-3-labelled glutamine uptake were observed during the first 2 h of incubation, resulting in values of 6.29 mu mol g(-1) fresh weight (FW) for zygotic embryos, 14.43 mu mol g(-1) FW for EC after 30 d, and 13.85 mu mol g(-1) FW for EC after 70 d. These results showed that the decreased levels of glutamine observed during the initial phase of development may be related to de novo protein synthesis and mobilisation during embryo maturation. The absorption of glutamine in the first 2 h of incubation also emphasises its involvement as an important source of N during morphogenesis of somatic and zygotic embryos.

Protein restriction inhibits gastric cell proliferation during rat postnatal growth in parallel to ghrelin changes

Objective: Gastric development depends directly on the proliferation and differentiation of epithelial cells, and these processes are controlled by multiple elements, such as diet, hormones, and growth factors. Protein restriction affects gastrointestinal functions, but its effects on gastric growth are not fully understood. Methods: The present study evaluated cell proliferation in the gastric epithelia of rats subjected to protein restriction since gestation. Because ghrelin is increasingly expressed from the fetal to the weaning stages and might be part of growth regulation, its distribution in the stomach of rats was investigated at 14, 30, and 50 d old. Results: Although the protein restriction at 8% increased the intake of food and body weight, the body mass was lower (P < 0.05). The stomach and intestine were also smaller but increased proportionately throughout treatment. Cell proliferation was estimated through DNA synthesis and metaphase indices, and lower rates (P < 0.05) were detected at the different ages. The inhibition was concomitant with a larger number of ghrelin-immunolabeled cells at 30 and 50 d postnatally. Conclusion: Protein restriction impairs cell proliferation in the gastric epithelium, and a ghrelin upsurge under this condition is parallel to lower gastric and body growth rates. (C) 2012 Elsevier Inc. All rights reserved.

Dental health in Northern Chile's Atacama oases: Evaluating the Middle Horizon (AD 500-1000) impact on local diet

As one of the few areas apt for horticulture in Northern Chile's arid landscape, the prehistory of the Atacama oases is deeply enmeshed with that of the inter-regional networks that promoted societal development in the south central Andes. During the Middle Horizon (AD 5001000), local populations experienced a cultural apex associated with a substantial increase in inter-regional interaction, population density, and quantity and quality of mortuary assemblages. Here, we test if this cultural peak affected dietary practices equally among the distinct local groups of this period. We examine caries prevalence and the degree of occlusal wear in four series recovered from three cemeteries. Our results show a reduction in the prevalence of caries for males among an elite subsample from Solcor 3 and the later Coyo 3 cemeteries. Dental wear tends to increase over time with the Late Middle Horizon/Late Intermediate Period cemetery of Quitor 6 showing a higher average degree of wear. When considered in concert with archaeological information, we concluded that the Middle Horizon was marked by dietary variability wherein some populations were able to obtain better access to protein sources (e.g., camelid meat). Not all members of Atacameno society benefited from this, as we note that this dietary change only affected men. Our results suggest that the benefits brought to the San Pedro oases during the Middle Horizon were not equally distributed among local groups and that social status, relationship to the Tiwanaku polity, and interment in particular cemeteries affected dietary composition. Am J Phys Anthropol, 2012. (C) 2012 Wiley Periodicals, Inc.

Regional and socioeconomic distribution of household food availability in Brazil, in 2008-2009

OBJECTIVE: To describe the regional and socioeconomic distribution of household food availability in Brazil. METHODS: Data from the 2008-2009 Household Budget Survey on food and beverage acquisition for household consumption, conducted by the Instituto Brasileiro de Geografia e Estatistica (Brazilian Institute of Geography and Statistics), were analyzed. The amounts of foods, recorded during seven consecutive days in the 55,970 sample households, were converted into calories and nutrients. Food quality indicators were constructed and analyzed according to the regional and socioeconomic strata of the Brazilian population. RESULTS: The amount of energy from protein was adequate in all regional and socioeconomic strata. On the other hand, an excess of free sugars and fats was observed in all regions of the country, especially in the Southern and Southeastern regions. The proportion of saturated fats was high in urban areas and consistent with the greater contribution of animal-derived products. Limited availability of fruits and vegetables was found in all regions. An increase in the fat content and reduction in carbohydrate content of the diet were observed with the increase in income. CONCLUSIONS: The negative characteristics of the Brazilian diet observed at the end of the first decade of the 21(st) century indicate the need to prioritize public policies for the promotion of healthy eating.

Cytoplasmic and extracellular expression of pharmaceutical-grade mycobacterial 65-kDa heat shock protein in Lactococcus lactis

Lactic acid bacteria (LAB) are an attractive and safe alternative for the expression of heterologous proteins, as they are nonpathogenic and endotoxin-free organisms. Lactococcus lactis, the LAB model organism, has been extensively employed in the biotechnology field for large-scale production of heterologous proteins, and its use as a "cell factory" has been widely studied. We have been particularly interested in the use of L. lactis for production of heat shock proteins (HSPs), which reportedly play important roles in the initiation of innate and adaptive immune responses. However, this activity has been questioned, as LPS contamination appears to be responsible for most, if not all, immunostimulatory activity of HSPs. In order to study the effect of pure HSPs on the immune system, we constructed recombinant L. lactis strains able to produce and properly address the Mycobacterium leprae 65-kDa HSP (Hsp65) to the cytoplasm or to the extracellular medium, using a xylose-induced expression system. Approximately 7 mg/L recombinant Hsp65 was secreted. Degradation products related to lactococcal HtrA activity were not observed, and the Limulus amebocyte lysate assay demonstrated that the amount of LPS in the recombinant Hsp65 preparations was 10-100 times lower than the permitted levels established by the U. S. Food and Drug Administration. These new L. lactis strains will allow investigation of the effects of M. leprae Hsp65 without the interference of LPS; consequently, they have potential for a variety of biotechnological, medical and therapeutic applications.

Effect of the classic ketogenic diet on the treatment of refractory epileptic seizures

Objective The ketogenic diet is used as a therapeutic alternative for the treatment of epilepsy in patients with refractory epilepsy. It simulates biochemical changes typical of fasting. The present study verified the nutritional impact of the ketogenic diet on children with refractory epilepsy. Methods Nutritional status data (dietary, biochemical and anthropometric measurements), seizure frequency, and adverse events were collected from the medical records and during outpatient clinic visits of children over a period of 36 months. Results Of the 29 children who initiated the ketogenic diet, 75.8% presented fewer seizures after one month of treatment. After six months, 48.3% of the patients had at least a 90.0% decrease in seizure frequency, and 50.0% of these patients presented total seizure remission. At 12 months, eight patients continued to show positive results, and seven of these children remained on the ketogenic diet for 24 months. There was an improvement of the nutritional status at 24 months, especially in terms of weight, which culminated with the recovery of proper weight-for-height. There were no significant changes in biochemical indices (total cholesterol and components, triglycerides, albumin, total protein, creatinine, glycemia, serum aspartate transaminase and serum alanine transaminase). Serum cholesterol levels increased significantly in the first month, fell in the following six months, and remained within the normal limits thereafter. Conclusion In conclusion, patients on the classic ketogenic diet for at least 24 months gained weight. Moreover, approximately one third of the patients achieved significant reduction in seizure frequency, and some patients achieved total remission.

High-Fat Diet Obesity Associated With Insulin Resistance Increases Cell Proliferation, Estrogen Receptor, and PI3K Proteins in Rat Ventral Prostate

In this study, we evaluated the effects of obesity and insulin resistance induced by a high-fat diet on prostate morphophysiology, focusing on cell proliferation, expression of androgen (AR) and estrogen receptors (ER) and proteins of the insulin signaling pathway. Adult male Wistar rats were fed a high-fat diet (20% fat) for 15 weeks, whereas control animals received a balanced diet (4% fat). Both groups were then divided and treated for 2 weeks with 1 mg/kg body weight/day of the aromatase inhibitor letrozole or vehicle only. The ventral prostate was analyzed with immunohistochemical, histopathological, stereological, and Western blotting methods. Obese rats showed insulin resistance, hyperinsulinemia, and reduced plasma testosterone levels. The incidence of prostatic intraepithelial neoplasia (PIN) was 2.7 times higher in obese rats and affected 0.4% of the gland compared with 0.1% PIN areas found in control rats. Obesity doubled cell proliferation in both prostate epithelium and stroma. AR content decreased in the prostate of obese rats and estrogen receptor beta (ER beta) increased in this group. Protein levels of insulin receptor substrate 1 and protein kinase B diminished in the obese group, whereas phosphatidylinositol 3-kinase (PI3K) increased significantly. Most structural changes observed in the prostate of obese rats normalized after letrozole treatment, except for increased stromal cell proliferation and ER beta expression, which might be associated with insulin resistance. This experimental model of obesity and insulin resistance induced by a high-fat diet increases cell proliferation in rat prostate. Such alterations are associated with decreased levels of AR and increased ER beta and PI3K proteins. This change can facilitate the establishment of proliferative lesions in rat prostate.

Administration of a murine diet supplemented with conjugated linoleic acid increases the expression and activity of hepatic uncoupling proteins

Daily intake of conjugated linoleic acid (CLA) has been shown to reduce body fat accumulation and to increase body metabolism; this latter effect has been often associated with the up-regulation of uncoupling proteins (UCPs). Here we addressed the effects of a CLA-supplemented murine diet (similar to 2 % CLA mixture, cis-9, trans-10 and trans-10, cis-12 isomers; 45 % of each isomer on alternating days) on mitochondrial energetics, UCP2 expression/activity in the liver and other associated morphological and functional parameters, in C57BL/6 mice. Diet supplementation with CLA reduced both lipid accumulation in adipose tissues and triacylglycerol plasma levels, but did not augment hepatic lipid storage. Livers of mice fed a diet supplemented with CLA showed high UCP2 mRNA levels and the isolated hepatic mitochondria showed indications of UCP activity: in the presence of guanosine diphosphate, the higher stimulation of respiration promoted by linoleic acid in mitochondria from the CLA mice was almost completely reduced to the level of the stimulation from the control mice. Despite the increased generation of reactive oxygen species through oxi-reduction reactions involving NAD(+)/NADH in the Krebs cycle, no oxidative stress was observed in the liver. In addition, in the absence of free fatty acids, basal respiration rates and the phosphorylating efficiency of mitochondria were preserved. These results indicate a beneficial and secure dose of CLA for diet supplementation in mice, which induces UCP2 overexpression and UCP activity in mitochondria while preserving the lipid composition and redox state of the liver.

Association between diet and polymorphisms in individuals with statin-controlled dyslipidaemia grouped according to oxidative stress biomarkers

The objective of this study was to investigate whether differences in diet and in single-nucleotide polymorphisms (SNPs) found in paraoxonase-1 (PON-1), 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), cholesterol ester transfer protein (CETP) and apolipoprotein E (APOE) genes, are associated with oxidative stress biomarkers and consequently with susceptibility of low-density cholesterol (LDL) to oxidation. A multivariate approach was applied to a group of 55 patients according to three biomarkers: plasma antioxidant activity, malondialdehyde and oxidized LDL (oxLDL) concentrations. Individuals classified in Cluster III showed the worst prognoses in terms of antioxidant activity and oxidative status. Individuals classified in Cluster I presented the lowest oxidative status, while individuals grouped in Cluster II presented the highest levels of antioxidant activity. No difference in nutrient intake was observed among the clusters. Significantly higher gamma- and delta-tocopherol concentrations were observed in those individuals with the highest levels of antioxidant activity. No single linear regression was statistically significant, suggesting that mutant alleles of the SNPs selected did not contribute to the differences observed in oxidative stress response. Although not statistically significant, the p value of the APO E coefficient for oxLDL response was 0.096, indicating that patients who carry the TT allele of the APO E gene tend to present lower plasma oxLDL concentrations. Therefore, the differences in oxidative stress levels observed in this study could not be attributed to diet or to the variant alleles of PON-1, CETP, HMGCR or APO E. This data supports the influence of gamma-tocopherol and delta-tocopherol on antioxidant activity, and highlights the need for further studies investigating APO E alleles and LDL oxidation.

Nitroglycerin drives endothelial nitric oxide synthase activation via the phosphatidylinositol 3-kinase/protein kinase B pathway

Nitroglycerin (GIN) has been clinically used to treat angina pectoris and acute heart episodes for over 100 years. The effects of GTN have long been recognized and active research has contributed to the unraveling of numerous metabolic routes capable of converting GIN to the potent vasoactive messenger nitric oxide. Recently, the mechanism by which minute doses of GIN elicit robust pharmacological responses was revisited and eNOS activation was implicated as an important route mediating vasodilation induced by low GTN doses (1-50 nM). Here, we demonstrate that at such concentrations the pharmacologic effects of nitroglycerin are largely dependent on the phosphatidylinositol 3-kinase, Akt/PKB, and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) signal transduction axis. Furthermore, we demonstrate that nitroglycerin-dependent accumulation of 3,4,5-InsP(3), probably because of inhibition of PTEN, is important for eNOS activation, conferring a mechanistic basis for GIN pharmacological action at pharmacologically relevant doses. (C) 2011 Elsevier Inc. All rights reserved.

Adhesion of Trypanosoma cruzi Trypomastigotes to Fibronectin or Laminin Modifies Tubulin and Paraflagellar Rod Protein Phosphorylation

Background: The unicellular parasite Trypanosoma cruzi is the causative agent of Chagas disease in humans. Adherence of the infective stage to elements of the extracellular matrix (ECM), as laminin and fibronectin, is an essential step in host cell invasion. Although members of the gp85/TS, as Tc85, were identified as laminin and fibronectin ligands, the signaling events triggered on the parasite upon binding to these molecules are largely unexplored. Methodology/Principal Findings: Viable infective parasites were incubated with laminin, fibronectin or bovine serum albumin for different periods of time and the proteins were separated by bidimensional gels. The phosphoproteins were envisaged by specific staining and the spots showing phosphorylation levels significantly different from the control were excised and identified by MS/MS. The results of interest were confirmed by immunoblotting or immunoprecipitation and the localization of proteins in the parasite was determined by immunofluorescence. Using a host cell-free system, our data indicate that the phosphorylation contents of T. cruzi proteins encompassing different cellular functions are modified upon incubation of the parasite with fibronectin or laminin. Conclusions/Significance: Herein it is shown, for the first time, that paraflagellar rod proteins and alpha-tubulin, major structural elements of the parasite cytoskeleton, are predominantly dephosphorylated during the process, probably involving the ERK1/2 pathway. It is well established that T. cruzi binds to ECM elements during the cell infection process. The fact that laminin and fibronectin induce predominantly dephosphorylation of the main cytoskeletal proteins of the parasite suggests a possible correlation between cytoskeletal modifications and the ability of the parasite to internalize into host cells.

Long-term leucine supplementation reduces fat mass gain without changing body protein status of aging rats

Objective: Aging is characterized by alterations in body composition such as an increase in body fat and decreases in muscle mass (sarcopenia) and bone density (osteopenia). Leucine supplementation has been shown to acutely stimulate protein synthesis and to decrease body fat. However, the long-term effect of consistent leucine supplementation is not well defined. This study investigated the effect of leucine supplementation during aging. Methods: Six-month-old rats were divided into three groups: an adult group (n = 10) euthanized at 6 mo of age, a leucine group (n = 16) that received a diet supplemented with 4% leucine for 40 wk, and a control group (n = 19) that received the control diet for 40 wk. The following parameters were evaluated: body weight, food intake, chemical carcass composition, indicators of acquired chronic diseases, and indicators of protein nutritional status. Results: Body weight and fat were lower in the leucine group after 40 wk of supplementation compared with the control group but still higher than in the adult group. The lipid and glycemic profiles were equally altered in the control and leucine groups because of aging. In addition, leucine supplementation did not affect the changes in protein status parameters associated with aging, such as decreases in body and muscle protein and total serum protein. Conclusion: The results indicate that leucine supplementation attenuates body fat gain during aging but does not affect risk indicators of acquired chronic diseases. Furthermore, supplemented animals did not show signs of a prevention of the decrease in lean mass associated with aging. (C) 2012 Elsevier Inc. All rights reserved.