Sociodemographic and obstetric factors associated with health-related quality of life of high-risk pregnant women.

OBJECTIVE: To evaluate the association between sociodemographic and obstetric factors and the health-related quality of life of pregnant women in high-risk prenatal care. METHODS: A cross-sectional study of women in high-risk prenatal care in Ceara, Brazil. The investigated outcomes were health-related quality of life, using the Medical Outcomes Study 36-item short-form health survey; the investigated covariates were sociodemographic and obstetric data. Associative analyses were performed using the Jamovi® software version 0.9. RESULTS: Of the 276 women included in the study, women with the following characteristics presented a better quality of life in some domain of the scale: age equal to or greater than 35 years, higher income per dependent, religious, living with three or fewer persons, with their own home, in primigestation, nulliparous, with no history of previous abortion, and with up to two living children. The regression model showed an association between the total scale score, which means a higher quality of life in women with age equal to or greater than 35 years and a higher income per dependent. CONCLUSION: The study identified sociodemographic and obstetric factors that may affect the quality of life of high-risk pregnant women, providing subsidies to health providers so that they can promote better prenatal care.

Efficient drug development of oseltamivir capsules based on process control, bioequivalence and PBPK modeling.

Oseltamivir phosphate is used to treat influenza. For registration of a generic product, bioequivalence studies are crucial, however, in vitro studies can sometimes replace the conventional human pharmacokinetic. To assess whether the dissolution profile is comparable with the in vivo release, physiologically based pharmacokinetic absorption models (PBPK) are being used. The aim of the study was to develop a generic capsule of oseltamivir phosphate 30 mg with process understanding and control, development of PBPK model and comparison of virtual bioequivalence study (VBE) to the real bioequivalence study that was also performed. For that, 30 mg capsules were prepared by wet granulation according to 22 full factorial design. The biobatch was prepared with the selected process and a batch was made with the API from the second manufacture. Both manufactures presented polymorph A and the second manufacture showed higher particle size. Product batches produced without adding water during granulation showed higher dissolution. The addition of water associated with higher conical mill speed, lowered the average weight of the capsules. The biobatch dissolution was similar to Tamiflu; also, they were bioequivalent. The crossover VBE between the biobatch and Tamiflu corroborated with the real bioequivalence study. The same result was found for the batch with higher particle size. PBPK model showed that computer simulations can help pharmaceutical companies to replace in vivo studies.

Early decrease in Cx36 is associated with increased cell adhesion molecules (CAMs) junctional content in mouse pancreatic islets after short-term high-fat diet feeding.

Cell-to-cell interactions mediated by intercellular junctions (IJs) are crucial for beta-cell functioning and proper insulin secretion, however, their role in type-2 diabetes is still unclear. This work aimed to evaluate the cellular distribution and expression of proteins associated with adherens (AJs) and gap junctions (GJs) in pancreatic islets of C57BL6 mice fed a high-fat (HF) diet. The administration of HF diet for 30 days induced an increase in body weight, post-prandial glycemia, insulinemia, glucose intolerance, and moderate insulin resistance associated with mild perturbations in insulin secretion. The intercellular content of the AJ-associated proteins (namely, E-, N-cadherins, and α-, ß-catenins) was significantly higher in islet cells of HF-fed mice. Inversely, the gap junctional content of Cx36 was significantly decreased, as revealed by immunofluorescence, which was paralleled by a reduction in the frequency of calcium oscillations in islets of prediabetic mice. In conclusion, the endocrine pancreas displays significant changes in the content of several junctional proteins at the cell-cell contact region following short-term HF diet administration, indicating that IJs may be involved in the adaptive response of beta cells seen during this state.

Offspring from trained male mice inherit improved muscle mitochondrial function through PPAR co-repressor modulation.

Aim Investigate whether inheritance of improved skeletal muscle mitochondrial function and its association with glycemic control are multigenerational benefits of exercise. MAIN METHODS: Male Swiss mice were subjected to 8 weeks of endurance training and mated with untrained females. KEY FINDINGS: Trained fathers displayed typical endurance training-induced adaptations. Remarkably, offspring from trained fathers also exhibited higher endurance performance, mitochondrial oxygen consumption, glucose tolerance and insulin sensitivity. However, PGC-1α expression was not increased in the offspring. In the offspring, the expression of the co-repressor NCoR1 was reduced, increasing activation of PGC-1α target genes. These effects correlated with higher DNA methylation at the NCoR1 promoter in both, the sperm of trained fathers and in the skeletal muscle of their offspring. SIGNIFICANCE: Higher skeletal muscle mitochondrial function is inherited by epigenetic de-activation of a key PGC-1α co-repressor.

Electrical therapies act on the Ca2+ /CaM signaling pathway to enhance bone regeneration with bioactive glass [S53P4] and allogeneic grafts.

This study aimed to investigate the application of low-intensity electrostimulation (ES) and electromagnetic stimulation (EM) associated with bioactive glass (BG) or allogeneic grafts (BB) in bone regeneration. A cell viability test on osteoblasts (UMR-106) was performed in the presence of BB and BG grafts associated with ES (10 µA/5 min) and EM (500 Hz/2 min). Critical defects (25 mm2 ) in calvaria were generated in male Wistar rats, and bone regeneration was evaluated on the 30th, 60th, and 120th days after surgery. Cell proliferation increased with the application of ES in both grafts and after EM with BG. Bone remodeling was more effective using the allogeneic graft in both therapies, with increased angiogenesis, osteoblast proliferation, and OPN expression in the BB + EM group. A higher number of osteoblasts and osteoclasts, and an increase in bone sialoprotein, Runx-2, and Opn gene expression were found in the BB + ES group. The BG graft associated with EM therapy had an increased proliferation of osteoblasts and increased expression of Runx-2 and Opn. Groups that had BG and ES therapy had increased numbers of osteoblasts, osteoclasts, and increased OPN expression. The expression of voltage-gated calcium channels increased in groups with ES, while calmodulin expression increased in therapies without grafting. ES and EM therapies favored the repair of bone defects upon grafting by improving angiogenesis, osteogenic gene expression, and tissue reorganization. Despite activating different pathways, both therapies increased the intracellular concentrations of calmodulin, leading to cell proliferation and bone regeneration.

Paternal Exercise Improves the Metabolic Health of Offspring via Epigenetic Modulation of the Germline.

BACKGROUND/AIMS: Epigenetic regulation is considered the main molecular mechanism underlying the developmental origin of health and disease's (DOHAD) hypothesis. Previous studies that have investigated the role of paternal exercise on the metabolic health of the offspring did not control for the amount and intensity of the training or possible effects of adaptation to exercise and produced conflicting results regarding the benefits of parental exercise to the next generation. We employed a precisely regulated exercise regimen to study the transgenerational inheritance of improved metabolic health. METHODS: We subjected male mice to a well-controlled exercise -training program to investigate the effects of paternal exercise on glucose tolerance and insulin sensitivity in their adult progeny. To investigate the molecular mechanisms of epigenetic inheritance, we determined chromatin markers in the skeletal muscle of the offspring and the paternal sperm. RESULTS: Offspring of trained male mice exhibited improved glucose homeostasis and insulin sensitivity. Paternal exercise modulated the DNA methylation profile of PI3Kca and the imprinted H19/Igf2 locus at specific differentially methylated regions (DMRs) in the skeletal muscle of the offspring, which affected their gene expression. Remarkably, a similar DNA methylation profile at the PI3Kca, H19, and Igf2 genes was present in the progenitor sperm indicating that exercise-induced epigenetic changes that occurred during germ cell development contributed to transgenerational transmission. CONCLUSION: Paternal exercise might be considered as a strategy that could promote metabolic health in the offspring as the benefits can be inherited transgenerationally.

Pegylated catalase as a potential alternative to treat vitiligo and UV induced skin damage.

The metabolic function of catalase (CAT) is to prevent oxidative damage to tissues through the hydrolysis of hydrogen peroxide, which is a strong oxidizing agent. It has been suggested as an alternative to treat skin diseases related to oxidative stress, such as vitiligo. Owing to the instability associated to the protein nature, topical use of CAT is challenging and, in this sense, PEGylation can be an interesting alternative. Here, we conjugated CAT to methoxy-poly(ethylene oxide) (mPEG) of 10, 20 and 40 kDa, by means of a nucleophilic attack of ε-amino groups to an electron-deficient carbonyl group of the reactive PEG, resulting in site specifically PEGylated bioconjugates. PEGylation yields ranged from 31% ± 2% for CAT-PEG40 to 59% ± 4% for CAT-PEG20 and were strongly affected by the reaction pH owing to the protonation/deprotonation state of primary amines of lysine and N-terminal residues. PEGylated conjugates were purified by size-exclusion chromatography (purity > 95%) and characterized by circular dichroism. Irrespectively of MW, PEG did not affected CAT secondary and tertiary structure, but a decrease in specific activity was observed, more pronounced when PEGs of higher MWs were used. However, this loss of activity is compensated by the increased long-term stability, with a gain of >5 times in t1/2. In vitro antioxidant activity of CAT-PEG20 showed complete elimination of lipid peroxidation at the skin upper layer (stratum corneum) suitable for a topical use to treat vitiligo, as well as other skin conditions related to oxidative stress.

Safety and Photoprotective Efficacy of a Sunscreen System Based on Grape Pomace (Vitis vinifera L.) Phenolics from Winemaking.

In winemaking, a large amount of grape pomace is produced that is rich in polyphenolics and highly beneficial for human health, as phenols are useful for skin ultraviolet (UV) protection. In this investigation, we evaluated the safety and clinical efficacy of a sunscreen system containing a grape pomace extract from Vitis vinifera L. as a bioactive ingredient. The recovery of phenolics in the waste was performed by percolation. Nine emulsions were developed using a factorial design and two were evaluated clinically: Formulation E, containing only UV filters (butylmethoxydibenzoyl methane, ethylhexyl methoxycinnamate and ethylhexyl dimethyl PABA), and F, with the extract at 10.0% w/w + UV filters. The antioxidant activity was determined by the DPPH assay and the in vitro efficacy was established by sun protection factor (SPF) measurements (Labsphere UV-2000S). Clinical tests were performed to determine safety (human repeated insult patch test) and to confirm efficacy (photoprotective effectiveness in participants). The results showed a synergistic effect between the sunscreen system and the extract on UVB protection and antioxidant activity. Both samples were considered safe. Formulation F was 20.59% more efficient in protecting skin against UVB radiation, taking approximately 21% more time to induce erythema compared to the extract-free sample.

Butyrospermum parkii butter increased the photostability and in vivo SPF of a molded sunscreen system.

BACKGROUND: Ultraviolet (UV) radiation exposure is related to skin and lip tumors. Therefore, the development of photoprotective lipstick formulations is of utmost importance. AIMS: Considering the biological properties of Shea butter (Butyrospermum parkii), we assessed its potential as an adjuvant in a molded lipstick sunscreen system by in vivo tests and photostability. PATIENTS/METHODS: Shea butter was used in a photoprotective lipstick formulation at two different concentrations (10.0% and 15.0% w/w) associated with ethylhexyl methoxycinnamate (EHM) and titanium dioxide. Skin compatibility was assessed in vivo. The in vivo SPF value was determined according to the current recognized method. Additionally, the photostability of EHM was determined by high-performance liquid chromatography. RESULTS: By the cutaneous compatibility, the product presented no interference with skin barrier and no adverse reactions, thus proving its safety. The in vivo SPF assay showed that the highest concentration of Shea butter increased the in vivo SPF value of the sample by 35%, demonstrating it to be a booster in photoprotective lipstick formulations. Also, Shea butter was proved to enhance the photostability of EHM, a commonly used UVB filter available in several countries. CONCLUSION: Shea butter increased the photostability and in vivo SPF of a molded lipstick sunscreen.

Influence of Shea (Butyrospermum parkii) butter, TiO2 and ethylhexyl methoxycinnamate on physical parameters and in vitro photoprotective efficacy.

BACKGROUND: The development of photoprotective lipsticks containing natural bioactive compounds is a relevant current strategy to increase sun protection factor (SPF) value and lower the concentration of chemical UV filters, known for promoting sensitivity reactions. AIMS: Twelve photoprotective lipsticks were developed by Design of Experiment (DOE) and characterized to verify the influence of Shea butter (Butyrospermum parkii), titanium dioxide (TiO2 ), and ethylhexyl methoxycinnamate (EHM) on physical parameters and in vitro photoprotective efficacy. METHODS: The influence of Shea butter, TiO2, and EHM was evaluated by several parameters, such as melting point, colorimetry, thermal analysis by DSC, texture analysis, and sunscreen activity estimated in vitro. RESULTS: The construction of prediction models was possible for the following responses: maximum force by the cantilever test at 25 and 45°C; maximum distance by hardness test at 25°C; slope value at 25 and 45°C by the cantilever test; and UVA/UVB ratio and in vitro SPF. TiO2 and EHM contributed to changes on the in vitro SPF value; however, unexpectedly, Shea butter had no influence on this efficacy parameter. CONCLUSION: The assay allowed us to observe the influence of the variables in the analysis and to develop a response prediction model for some of the parameters assessed.

Comments to Angulo et al. 2016 on "Sea-level fluctuations and coastal evolution in the state of Rio de Janeiro, southeastern - Brazil" by Castro et al. 2014.

Interpretation of sea-level indicators is essential when studying paleo sea-level fluctuations during the Holocene. Sea-level indicators may have different origins, such as geological (beachrocks) and biological (vermetids and barnacles). In order to reconstruct paleo sea-level, it is necessary to attribute an indicative meaning to each sea-level indicator. This paper aims to discuss issues raised by Angulo et al. (2016) regarding to the sea-level fluctuations curve proposed by Castro et al. (2014) to the Rio de Janeiro State coast, Brazilian southeast. The key issue that deserves posing is that local or regional curves cannot be built based on large scale (global) RSL geophysical models even in places of steady crust like Brazil. Here, we put into question the relative sea-level fluctuation curve model proposed by Angulo et al. (2006, 2016) to the coast of Rio de Janeiro State and Pernambuco State. It is strengthened the proposal of using different origins indicators on RSL vertical variation, georeferenced by high precision altitude GPS, adjusted by Brazilian Geodetic System benchmarks, maintained by the Brazilian Institute of Geography and Statistics - IBGE. All issues regarding the curve drawn by Castro et al. (2014) are answered based on field data, laboratory analytical techniques, radiocarbon dating as well as relevant literature.

Translational Science: How experimental research has contributed to the understanding of spontaneous Physical Activity and Energy Homeostasis

Abstract Spontaneous physical activity (SPA) consists of all daily living activities other than volitional exercise (e.g. sports and fitness-related activities). SPA is an important component of energy expenditure and may protect from overweight and obesity. Little is known about the biological regulation of SPA, but animal researchhas contributedsignificantly to expand our knowledge in this field. Studies in rodents have shown that SPA is influenced by nutrients and volitional exercise. High-fat diet seems to decrease SPA, which contributes to weigh gain. Volitional exercisemayalso reduce SPA, helping to explain the commonly reported low efficiency of exercise to cause weight loss, and highlighting the need to finda volume/intensity of exercise to maximize total daily energy expenditure. Animal studieshave also allowed for the identification of some brain areas and chemical mediatorsinvolved in SPA regulation. These discoveries could enable the development of new therapeutics aiming to enhance SPA.(AU)

Toxicological evaluation of ametryn effects in Wistar rats.

São Paulo state, Brazil, is one of the main areas of sugar cane planting in the world. Extensive use of ametryn, a triazine herbicide, in sugar cane agriculture and the properties of this herbicide suggest it could be present in the environment as a potential contaminant of soil, surface water, groundwater, and river sediment. In order to clarify the mechanism through which ametryn could be toxic, an in vivo study with Wistar rats was conducted using hematological, biochemical, molecular, morphological and genotoxic approaches. For this purpose, two sub-lethal ametryn concentrations (15 mg and 30 mg/kg/day) were administered to 42 rats divided into three groups (n=12) by gavage during 56 days, whereupon blood, liver and bone marrow were collected. The results showed ametryn genotoxic activity by in vivo micronuclei testing. This event probably occurred as consequence of oxidative stress induction demonstrated by GSTM1 transcript levels increase (indicating complexation between ametryn and/or metabolites with GSH) and by SOD activity decrease. Also, Mn-SOD transcripts were increased, probably avoiding mtDNA damage caused by EROS. These mechanisms displayed hepatic stellate cell (HSCs) activation because two major biomarkers were regulated, connexin and cadherin. N-cad transcripts were increased on both exposed groups while E-cad decreased in the T1 group, indicating epithelial-to-mesenchymal transition. In addition, Cx43 transcripts were decreased suggesting an increase in collagen content. Volumetric proportion of sinusoids was significantly decreased in T1 group and no significant alteration in hepatocyte volume was observed, indicating an increase in the space of Disse, due to fibrosis. Hepatocyte nuclei showed significant decrease in diameter and volume. Few hematological alterations were found. We emphasize the importance of other approaches, such as cell death and proliferation assays, so that ametryn toxicity can better be understood.

Endurance training inhibits insulin clearance and IDE expression in Swiss mice.

INTRODUCTION: Endurance training improves peripheral insulin sensitivity in the liver and the skeletal muscle, but the mechanism for this effect is poorly understood. Recently, it was proposed that insulin clearance plays a major role in both glucose homeostasis and insulin sensitivity. Therefore, our goal was to determine the mechanism by which endurance training improves insulin sensitivity and how it regulates insulin clearance in mice. METHODS: Mice were treadmill-trained for 4 weeks at 70-80% of maximal oxygen consumption (VO2 max) for 60 min, 5 days a week. The glucose tolerance and the insulin resistance were determined using an IPGTT and an IPITT, respectively, and the insulin decay rate was calculated from the insulin clearance. Protein expression and phosphorylation in the liver and the skeletal muscle were ascertained by Western blot. RESULTS: Trained mice exhibited an increased VO2 max, time to exhaustion, glucose tolerance and insulin sensitivity. They had smaller fat pads and lower plasma concentrations of insulin and glucose. Endurance training inhibited insulin clearance and reduced expression of IDE in the liver, while also inhibiting insulin secretion by pancreatic islets. There was increased phosphorylation of both the canonical (IR-AKT) and the non-canonical (CaMKII-AMPK-ACC) insulin pathways in the liver of trained mice, whereas only the CaMKII-AMPK pathway was increased in the skeletal muscle. CONCLUSION: Endurance training improved glucose homeostasis not only by increasing peripheral insulin sensitivity but also by decreasing insulin clearance and reducing IDE expression in the liver.

Leucine supplementation does not affect protein turnover and impairs the beneficial effects of endurance training on glucose homeostasis in healthy mice.

Endurance exercise training as well as leucine supplementation modulates glucose homeostasis and protein turnover in mammals. Here, we analyze whether leucine supplementation alters the effects of endurance exercise on these parameters in healthy mice. Mice were distributed into sedentary (C) and exercise (T) groups. The exercise group performed a 12-week swimming protocol. Half of the C and T mice, designated as the CL and TL groups, were supplemented with leucine (1.5 % dissolved in the drinking water) throughout the experiment. As well known, endurance exercise training reduced body weight and the retroperitoneal fat pad, increased soleus mass, increased VO2max, decreased muscle proteolysis, and ameliorated peripheral insulin sensitivity. Leucine supplementation had no effect on any of these parameters and worsened glucose tolerance in both CL and TL mice. In the soleus muscle of the T group, AS-160(Thr-642) (AKT substrate of 160 kDa) and AMPK(Thr-172) (AMP-Activated Protein Kinase) phosphorylation was increased by exercise in both basal and insulin-stimulated conditions, but it was reduced in TL mice with insulin stimulation compared with the T group. Akt phosphorylation was not affected by exercise but was lower in the CL group compared with the other groups. Leucine supplementation increased mTOR phosphorylation at basal conditions, whereas exercise reduced it in the presence of insulin, despite no alterations in protein synthesis. In trained groups, the total FoxO3a protein content and the mRNA for the specific isoforms E2 and E3 ligases were reduced. In conclusion, leucine supplementation did not potentiate the effects of endurance training on protein turnover, and it also reduced its positive effects on glucose homeostasis.

Early cytotoxic and genotoxic effects of atrazine on Wistar rat liver: a morphological, immunohistochemical, biochemical, and molecular study.

Risk assessments suggest that intermediate and long-term exposure to triazine herbicides and its metabolites through water can cause severe damage to human health. The objective of this study was to investigate the possible effects of atrazine on Wistar rats submitted to subacute treatment. For this purpose, the activity of catalase and alanine aminotransferase was quantified, and the effect of the herbicide on cell membranes was examined based on the measurement of lipid peroxidation and consequent formation of malondialdehyde and on the mRNA expression of antioxidant enzymes (Mn-superoxide dismutase [SOD] and GSTM1) and connexins. In addition, we evaluated histopathological alterations in the liver, cellular expression of SOD and glutathione (GST), activation of heat shock proteins (HSPs) by immunohistochemistry, and the induction of apoptosis. The genotoxic potential of the herbicide was investigated by the micronucleus test in bone marrow smears. Adult male Wistar rats were treated with an aqueous solution of atrazine at a concentration of 400mg/kg/day, by gavage, for 14 consecutive days. Control groups were also included. The results showed an increase of catalase levels and maintenance of the expression of antioxidant enzymes (SOD and GST). In addition, lipid peroxidation, hepatic tissue degeneration, activation of HSP90, increased levels of connexin mRNA, and genotoxicity were observed. In conclusion, atrazine induced early hepatic oxidative stress that triggered defense mechanisms to maintain the morphophysiological integrity of the liver. Further studies are needed to better understand the effects of this herbicide on human health.

Taurine supplementation restores glucose and carbachol-induced insulin secretion in islets from low-protein diet rats: involvement of Ach-M3R, Synt 1 and SNAP-25 proteins.

Isolated islets from low-protein (LP) diet rats showed decreased insulin secretion in response to glucose and carbachol (Cch). Taurine (TAU) increases insulin secretion in rodent islets with a positive effect upon the cholinergic pathway. Here, we investigated the effect of TAU administration upon glucose tolerance and insulin release in rats fed on a normal protein diet (17%) without (NP) or with 2.5% of TAU in their drinking water (NPT), and LP diet fed rats (6%) without (LP) or with TAU (LPT). Glucose tolerance was found to be higher in LP, compared to NP rats. However, plasma glucose levels, during ipGTT, in LPT rats were similar to those of controls. Isolated islets from LP rats secreted less insulin in response to increasing glucose concentrations (2.8-22.2 mmol/L) and to 100 µmol/L Cch. This lower secretion was accompanied by a reduction in Cch-induced internal Ca(2+) mobilization. TAU supplementation prevents these alterations, as judged by the higher secretion induced by glucose or Cch in LPT islets. In addition, Ach-M3R, syntaxin 1 and synaptosomal associated protein of 25 kDa protein expressions in LP were lower than in NP islets. The expressions of these proteins in LPT were normalized. Finally, the sarcoendoplasmatic reticulum Ca(2+)-ATPase 3 protein expression was higher in LPT and NPT, compared with controls. In conclusion, TAU supplementation to LP rats prevented alterations in glucose tolerance as well as in insulin secretion from isolated islets. The latter effect involves the normalization of the cholinergic pathway, associated with the preservation of exocytotic proteins.

N-acetylcysteine protects pancreatic islet against glucocorticoid toxicity.

OBJECTIVES: Reactive oxygen species (ROS) are involved in many physiological and pathological processes. In the present study, we analysed whether the synthetic glucocorticoid dexamethasone induces oxidative stress in cultured pancreatic islets and whether the effects of dexamethasone on insulin secretion, gene expression, and viability can be counteracted by concomitant incubation with N-acetylcysteine (NAC). METHODS: ROS production was measured by dichlorofluorescein (DCFH-DA) assay, insulin secretion by radioimmunoassay, intracellular calcium dynamics by fura-2-based fluorescence, gene expression by real-time polymerase chain reaction analyses and cell viability by the MTS assay. RESULTS: Dexamethasone (Dexa) increased ROS production and decreased glucose-stimulated insulin secretion after 72 hours incubation. Intracellular ROS levels were decreased and the insulin secretion capacity was recovered by concomitant treatment with Dexa+NAC. The total insulin content and intracellular Ca2+ levels were not modulated in either Dexa or Dexa+NAC groups. There was a decrease in the NAD(P)H production, used as an indicator of viability, after dexamethasone treatment. Concomitant incubation with NAC returned viability to control levels. Dexa also decreased synaptotagmin VII (SYT VII) gene expression. In contrast, the Dexa+NAC group demonstrated an increased expression of SYT VII compared to controls. Surprisingly, treatment with NAC decreased the gene expression of the antioxidant enzyme copper zinc superoxide dismutase soluble. DISCUSSION: Our results indicate that dexamethasone increases ROS production, decreases viability, and impairs insulin secretion in pancreatic rat islets. These effects can be counteracted by NAC, which not only decreases ROS levels but also modulates the expression of genes involved in the secretory pathway and those coding for antioxidant enzymes.

CNTF protects MIN6 cells against apoptosis induced by Alloxan and IL-1ß through downregulation of the AMPK pathway.

Our group previously demonstrated that CNTF protects pancreatic islets against apoptosis induced by IL1ß. In addition, it is known that AMPK knockout protects beta cells from IL1ß-mediated apoptosis, however how AMPK activation leads to apoptosis remains unknown. The present study was designed to investigate the possible role of AMPK pathway modulation in CNTF protective effects against apoptosis induced by IL1ß or Alloxan and how AMPK activation leads to beta cells apoptosis. First, we observed that apoptosis of MIN6 cells, induced by Alloxan as well as IL-1ß, requires activation of the AMPK pathway, and also that CNTF protective effects are dependent on downregulation of AMPK. In addition, we found that Alloxan induces AMPK differently from IL1ß, as Alloxan acts mainly through CaMKII while IL1ß acts through LKB1 phosphorylation. Meanwhile, CNTF by itself inhibited the AMPK pathway and protected against AMPK activation induced by Alloxan or IL1ß via downregulation of CaMKII. Finally, AMPK-dependent MIN6 cell apoptosis, induced by IL1ß or Alloxan, required increased iNOS expression, an effect that was reversed by CNTF downregulation of AMPK pathway and iNOS expression. In conclusion, IL1ß upregulates the LKB1-AMPK-INOS pathway, while Alloxan acts through CaMKII-AMPK-INOS, both ultimately leading to beta cell death. In this context, CNTF protects beta cells against apoptosis, induced by either IL1ß or Alloxan, through downregulation of the CaMKII-AMPK-INOS pathway.

Reduced expression of SIRT1 is associated with diminished glucose-induced insulin secretion in islets from calorie-restricted rats.

Alterations in food intake such as caloric restriction modulate the expression of SIRT1 and SIRT4 proteins that are involved in pancreatic ß-cell function. Here, we search for a possible relationship between insulin secretion and the expression of SIRT1, SIRT4, PKC and PKA in islets from adult rats submitted to CR for 21 days. Rats were fed with an isocaloric diet (CTL) or received 60% (CR) of the food ingested by CTL. The dose-response curve of insulin secretion to glucose was shifted to the right in the CR compared with CTL islets (EC(50) of 15.1±0.17 and 10.5±0.11 mmol/L glucose). Insulin release by the depolarizing agents arginine and KCl was reduced in CR compared with CTL islets. Total islet insulin content and glucose oxidation were also reduced in CR islets. Leucine-stimulated secretion was similar in both groups, slightly reduced in CR islets stimulated by leucine plus glutamine but higher in CR islets stimulated by ketoisocaproate (KIC). Insulin secretion was also higher in CR islets stimulated by carbachol, compared with CTL islets. No differences in the rise of cytosolic Ca(2+) concentrations stimulated by either glucose or KCl were observed between groups of islets. Finally, SIRT1, but not SIRT4, protein expression was lower in CR compared with CTL islets, whereas no differences in the expression of PKC and PKA proteins were observed. In conclusion, the lower insulin secretion in islets from CR rats was, at least in part, due to an imbalance between the expression of SIRT1 and SIRT4.