Moderate chronic sleep perturbation impairs glucose and lipid homeostasis in rats.

STUDY OBJECTIVES: Sleep deprivation is a potential risk factor for metabolic diseases, including obesity and type 2 diabetes. We evaluated the impacts of moderate chronic sleep deprivation on glucose and lipid homeostasis in adult rats. METHODS: Wistar rats (both sexes) were sleep-perturbed daily for two hours at the early (06:00-08:00) and the late light cycle (16:00-18:00) five days a week (except weekends) for four weeks. RESULTS: Sleep perturbation (SP) resulted in reduced body weight gain in both sexes, associated with altered food intake and reduced adiposity. SP did not alter the short- or long-term memories or cause anxiogenic behavior. No major changes were observed in the plasma insulin, leptin, triacylglycerol, non-esterified fatty acids and blood glucose upon SP. After SP, females exhibited a transitory glucose intolerance, while males became glucose intolerant at the end of the experimental period. Male rats also developed higher insulin sensitivity at the end of the SP protocol. Morphometric analyses revealed no changes in hepatic glycogen deposition, pancreatic islet mass, islet-cell distribution, or adrenal cortex thickness in SP rats from both sexes, except for lower adipocyte size compared with controls. We did not find homogeneous changes in the relative expression of circadian and metabolic genes in muscle or hepatic tissues from the SP rats. CONCLUSIONS: Moderate chronic SP reduces visceral adiposity and causes glucose intolerance with a more pronounced impact on male rats, reinforcing the metabolic risks of exposure to sleep disturbances.

Zein nanoparticles as oral carrier for mometasone furoate delivery.

Mometasone furoate (MF) is a synthetic glucocorticoid used clinically to treat specific inflammatory disorders including superior and inferior respiratory tract. Due to its poor bioavailability we further investigated whether nanoparticles (NPs) made of zein protein may constitute a safe and effective choice to incorporate MF. Thus, in this work, we loaded MF into zein NPs aiming to evaluate possible advantages that could result from oral delivery and extend the range of MF application such as inflammatory gut diseases. MF-loaded zein NPs presented an average size in the range of 100 and 135 nm, narrow size distribution (polydispersity index < 0.300), zeta potential of around + 10 mV and association efficiency of MF over 70%. Transmission electron microscopy imaging revealed that NPs had a round shape and presented a smooth surface. The zein NPs showed low MF release in a buffer that mimics the gastric condition (pH = 1.2) and slower and controlled MF release in the intestinal condition (pH = 6.8). The short and intermediate safety of zein NPs was confirmed assessing the incubation against Caco-2 and HT29-MTX intestinal cells up to 24 h. Permeability studies of MF across Caco-2/HT29-MTX co-culture monolayer evidenced that zein NPs modulated MF transport across cell monolayer resulting in a stronger and prolonged interaction with mucus, potentially extending the time of absorption and overall local and systemic bioavailability. Overall, zein NPs showed to be suitable to carry MF to the intestine and future studies can be developed to investigate the use of MF-loaded zein NPs to treat intestinal inflammatory diseases.

Coadministration of olanzapine causes minor impacts on the diabetogenic outcomes induced by dexamethasone treatment in rats.

AIMS: Investigate whether the coadministration of olanzapine exacerbates the diabetogenic effects of dexamethasone, two agents used in the antiemetic cocktails indicated to mitigate the adverse effects of chemotherapy. MAIN METHODS: Adult Wistar rats (both sexes) were treated daily with dexamethasone (1 mg/kg, body mass (b.m.), intraperitoneal (i.p.)) with or without olanzapine (10 mg/kg, b.m., orogastric (o.g.)) for 5 consecutive days. During and at the end of the treatment, we evaluated biometric data and parameters involving glucose and lipid metabolism. KEY FINDINGS: Dexamethasone treatment resulted in glucose and lipid intolerance, higher plasma insulin and triacylglycerol levels, higher content of hepatic glycogen and fat, and higher islet mass in both sexes. These changes were not exacerbated by concomitant treatment with olanzapine. However, coadministration of olanzapine worsened the weight loss and plasma total cholesterol in males, while in females resulted in lethargy, higher plasma total cholesterol, and higher hepatic triacylglycerol release. SIGNIFICANCE: Coadministration of olanzapine does not exacerbate any diabetogenic dexamethasone effect on glucose metabolism and exerts a minor impact on the lipid homeostasis of rats. Our data favor the addition of olanzapine in the antiemetic cocktail considering the low incidence of metabolic adverse effects for the period and dosage analyzed in male and female rats.

Oral mometasone furoate administration preserves anti-inflammatory action with fewer metabolic adverse effects in rats.

BACKGROUND: Exogenous glucocorticoids (CGs) possess relevant therapeutic effects but exert diabetogenic actions when in excess. Thus, ligands with potential therapeutic applications and fewer adverse effects are needed. To this, we analyzed whether mometasone furoate (MF), a CG expected to cause fewer side effects, given through systemic routes, could maintain the anti-inflammatory actions without relevant repercussions on metabolism. METHODS: The anti-inflammatory effect of MF was evaluated with both peritonitis and colitis models in rodents. Glucose and lipid metabolism were investigated in male and female rats treated daily with MF with different doses and routes of administration for seven days. The involvement of glucocorticoid receptor (GR) on MF actions was assessed in animals pretreated with mifepristone. Also, the potential reversibility of the adverse effects was assessed. Dexamethasone was used as a positive control. RESULTS: MF treatment resulted in glucose intolerance in male rats treated through intraperitoneal (ip) but not oral gavage route (og). In female rats, none of the routes led to glucose intolerance. MF treatment attenuated insulin sensitivity and increased pancreatic ß-cell mass, regardless of the sex and route of administration. MF treatment through og route did not result in dyslipidemia, as observed in rats treated through the ip route (both sexes). The anti-inflammatory and metabolic adverse effects of MF were GR-dependent, and metabolic outcomes altered by MF administration were reversible. CONCLUSION: MF maintains anti-inflammatory activity when administered by systemic routes and exerts less impact on metabolism when administered orally in male and female rats, effects that are GR-dependent and reversible. Category: Metabolic Disorders and Endocrinology.

Preconception exposure to malathion and glucose homeostasis in rats: Effects on dams during pregnancy and post-term periods, and on their progeny.

Understanding the individual and global impact of pesticides on human physiology and the different stages of life is still a challenge in environmental health. We analyzed here whether administration of the organophosphate insecticide malathion before pregnancy could affect glucose homeostasis during pregnancy and, in addition, generate possible later consequences in mothers and offspring. For this, adult Wistar rats were allocated into two groups and were treated daily (intragastric) with malathion (14 or 140 mg/kg, body mass (bm)) for 21-25 days. Corn oil was used as vehicle in the Control group. Subgroups were defined based on the absence (nulliparous) or presence (pregnant) of a copulatory plug. Pregnant rats were followed by an additional period of 2 months after the term (post-term), without continuing malathion treatment. Fetuses and adult offspring of males and females were also evaluated. We ran an additional experimental design with rats exposed to malathion before pregnancy at a dose of 0.1 mg/kg bm. Malathion exposure resulted in glucose intolerance in the mothers during pregnancy and post-term period, regardless of the exposure dose. This was accompanied by increased visceral adipose tissue mass, dyslipidemia, unchanged pancreatic ß-cell mass, and varying insulin responses to glucose in vivo. The number of total newborns and birthweight was not affected by malathion exposure. Adult offspring from both sexes also became glucose-intolerant, regardless of the pesticide dose their dams were exposed to. This alteration could be associated with changes at the epigenomic level, as reduced hepatic mRNA content of DNA methylases and demethylases was found. We demonstrated that periconceptional exposure to malathion with doses aiming to mimic from work environment to indirect contamination predisposes progenitors and offspring rats to glucose intolerance. Thus, we conclude that subchronic exposure to malathion is a risk factor for gestational diabetes and prediabetes later in life.

Glucocorticoids and glucolipotoxicity alter the DNA methylome and function of human EndoC-ßH1 cells.

AIMS: Synthetic glucocorticoids, including dexamethasone (DEX), are clinically prescribed due to their immunoregulatory properties. In excess they can perturb glucose homeostasis, with individuals predisposed to glucose intolerance more sensitive to these negative effects. While DEX is known to negatively impact ß-cell function, it is unclear how. Hence, our aim was to investigate the effect of DEX on ß-cell function, both alone and in combination with a diabetogenic milieu in the form of elevated glucose and palmitate. MAIN METHODS: Human pancreatic EndoC-ßH1 cells were cultured in the presence of high glucose and palmitate (glucolipotoxicity) and/or a pharmacological concentration of DEX, before functional and molecular analyses. KEY FINDINGS: Either treatment alone resulted in reduced insulin content and secretion, while the combination of DEX and glucolipotoxicity promoted a strong synergistic effect. These effects were associated with reduced insulin biosynthesis, likely due to downregulation of PDX1, MAFA, and the proinsulin converting enzymes, as well as reduced ATP response upon glucose stimulation. Genome-wide DNA methylation analysis found changes on PDE4D, MBNL1 and TMEM178B, all implicated in ß-cell function, after all three treatments. DEX alone caused very strong demethylation of the glucocorticoid-regulated gene ZBTB16, also known to influence the ß-cell, while the combined treatment caused altered methylation of many known ß-cell regulators and diabetes candidate genes. SIGNIFICANCE: DEX treatment and glucolipotoxic conditions separately alter the ß-cell epigenome and function. The combination of both treatments exacerbates these changes, showing that caution is needed when prescribing potent glucocorticoids in patients with dysregulated metabolism.

The effects of macronutrients composition on hormones and substrates during a meal tolerance test in drug-naive and sitagliptin-treated individuals with type 2 diabetes: a randomized crossover study

ABSTRACT Objectives: To evaluate the effect of sitagliptin treatment in early type 2 diabetes mellitus (T2DM) and the impact of different macronutrient compositions on hormones and substrates during meal tolerance tests (MTT). Materials and methods: Half of the drug-naive patients with T2DM were randomly assigned for treatment with 100 mg of sitagliptin, q.d., or placebo for 4 weeks and then submitted to 3 consecutive MTT intercalated every 48 h. The MTTs differed in terms of macronutrient composition, with 70% of total energy from carbohydrates, proteins, or lipids. After 4 weeks of washout, a crossover treatment design was repeated. Both patients and researchers were blinded, and a repeated-measures ANOVA was employed for statistical analysis. Results: Sitagliptin treatment reduced but did not normalize fasting and post-meal glucose values in the three MTTs, with lowered area-under-glucose-curve values varying from 7% to 15%. The sitagliptin treatment also improved the insulinogenic index (+86%) and the insulin/glucose (+25%), glucagon-like peptide-1/glucose (+46%) incremental area under the curves. Patients with early T2DM maintained the lowest glucose excursion after a protein- or lipid-rich meal without any major change in insulin, C-peptide, glucagon, or NEFA levels. Conclusion: We conclude that sitagliptin treatment is tolerable and contributes to better control of glucose homeostasis in early T2DM, irrespective of macronutrient composition. The blood glucose excursion during meal ingestion is minimal in protein- or fat-rich meals, which can be a positive ally for the management of T2DM. Clinical trial no: NCT00881543

The effects of macronutrients composition on hormones and substrates during a meal tolerance test in drugnaive and sitagliptin-treated individuals with type 2 diabetes: a randomized crossover study.

Objective: To evaluate the effect of sitagliptin treatment in early type 2 diabetes mellitus (T2DM) and the impact of different macronutrient compositions on hormones and substrates during meal tolerance tests (MTT). Methods: Half of the drug-naive patients with T2DM were randomly assigned for treatment with 100 mg of sitagliptin, q.d., or placebo for 4 weeks and then submitted to 3 consecutive MTT intercalated every 48 h. The MTTs differed in terms of macronutrient composition, with 70% of total energy from carbohydrates, proteins, or lipids. After 4 weeks of washout, a crossover treatment design was repeated. Both patients and researchers were blinded, and a repeated-measures ANOVA was employed for statistical analysis. Results: Sitagliptin treatment reduced but did not normalize fasting and post-meal glucose values in the three MTTs, with lowered area-under-glucose-curve values varying from 7% to 15%. The sitagliptin treatment also improved the insulinogenic index (+86%) and the insulin/glucose (+25%), glucagon-like peptide-1/glucose (+46%) incremental area under the curves. Patients with early T2DM maintained the lowest glucose excursion after a protein- or lipid-rich meal without any major change in insulin, C-peptide, glucagon, or NEFA levels. Conclusion: We conclude that sitagliptin treatment is tolerable and contributes to better control of glucose homeostasis in early T2DM, irrespective of macronutrient composition. The blood glucose excursion during meal ingestion is minimal in protein- or fat-rich meals, which can be a positive ally for the management of T2DM. Clinical trial no: NCT00881543.

Pep19 Has a Positive Effect on Insulin Sensitivity and Ameliorates Both Hepatic and Adipose Tissue Phenotype of Diet-Induced Obese Mice.

Peptide DIIADDEPLT (Pep19) has been previously suggested to improve metabolic parameters, without adverse central nervous system effects, in a murine model of diet-induced obesity. Here, we aimed to further evaluate whether Pep19 oral administration has anti-obesogenic effects, in a well-established high-fat diet-induced obesity model. Male Swiss mice, fed either a standard diet (SD) or high-fat diet (HFD), were orally administrated for 30 consecutive days, once a day, with saline vehicle or Pep19 (1 mg/kg). Next, several metabolic, morphological, and behavioral parameters were evaluated. Oral administration of Pep19 attenuated HFD body-weight gain, reduced in approximately 40% the absolute mass of the endocrine pancreas, and improved the relationship between circulating insulin and peripheral insulin sensitivity. Pep19 treatment of HFD-fed mice attenuated liver inflammation, hepatic fat distribution and accumulation, and lowered plasma alanine aminotransferase activity. The inguinal fat depot from the SD group treated with Pep19 showed multilocular brown-fat-like cells and increased mRNA expression of uncoupling protein 1 (UCP1), suggesting browning on inguinal white adipose cells. Morphological analysis of brown adipose tissue (BAT) from HFD mice showed the presence of larger white-like unilocular cells, compared to BAT from SD, Pep19-treated SD or HFD mice. Pep19 treatment produced no alterations in mice behavior. Oral administration of Pep19 ameliorates some metabolic traits altered by diet-induced obesity in a Swiss mice model.

Antidepressant-like activity of gestational administration of vitamin D is suppressed by prenatal overexposure to dexamethasone in female Wistar rats.

Overexposure to glucocorticoids during gestation can lead to long-term mental disorders. Given the higher prevalence of depression in females, we investigated whether late gestational administration of dexamethasone could generate a depressive-like phenotype in the adult female offspring and if vitamin D could have a neuroprotective effect in this context. Pregnant rats received vitamin D (VitD, 500 IU/day) or vehicle (CTL) during gestation. Other pregnant rats received dexamethasone (Dex 0.1 mg/kg/ - 14th to the 19th gestational day) or dexamethasone + vitamin D (DexVitD). The offspring were tested for anhedonia (sucrose preference) and depressive-like behavior (forced swimming test) at postnatal months (PNM) 3, 6 and 12. Components of the serotonergic system, as well as glucocorticoids' receptors, were evaluated in the dorsal raphe nucleus at PNM 6 and 12. Prenatal vitamin D and dexamethasone increased sucrose preference at PNM 12. Prenatal vitamin D had an antidepressant-like effect at PNM 3 in rats overexposed to dexamethasone. However, at PNM 12, this effect was blunted in the DexVitD group. Prenatal dexamethasone reduced the protein content of SERT, TPH, and 5-HT1A receptors in the dorsal raphe nucleus at 6 but not at 12 PNM. The glucocorticoids' receptors expression was similar in all groups. We concluded that prenatal overexposure to dexamethasone does not change emotional behaviors in females, but it blunts the antidepressant-like effect of gestational vitamin D in an age-dependent manner. The antidepressant-like activity of vitamin D in the offspring was not related either to alterations of the serotonergic system or the glucocorticoids' receptors expression in the dorsal raphe nucleus.

The Effects of Aging on Male Mouse Pancreatic ß-Cell Function Involve Multiple Events in the Regulation of Secretion: Influence of Insulin Sensitivity.

Aging is associated with a decline in peripheral insulin sensitivity and an increased risk of impaired glucose tolerance and type 2 diabetes. During conditions of reduced insulin sensitivity, pancreatic ß cells undergo adaptive responses to increase insulin secretion and maintain euglycemia. However, the existence and nature of ß-cell adaptations and/or alterations during aging are still a matter of debate. In this study, we investigated the effects of aging on ß-cell function from control (3-month-old) and aged (20-month-old) mice. Aged animals were further categorized into 2 groups: high insulin sensitive (aged-HIS) and low insulin sensitive (aged-LIS). Aged-LIS mice were hyperinsulinemic, glucose intolerant, and displayed impaired glucose-stimulated insulin and C-peptide secretion, whereas aged-HIS animals showed characteristics in glucose homeostasis similar to controls. In isolated ß cells, we observed that glucose-induced inhibition of KATP channel activity was reduced with aging, particularly in the aged-LIS group. Glucose-induced islet NAD(P)H production was decreased in aged mice, suggesting impaired mitochondrial function. In contrast, voltage-gated Ca2+ currents were higher in aged-LIS ß cells, and pancreatic islets of both aged groups displayed increased glucose-induced Ca2+ signaling and augmented insulin secretion compared with controls. Morphological analysis of pancreas sections also revealed augmented ß-cell mass with aging, especially in the aged-LIS group, as well as ultrastructural ß-cell changes. Altogether, these findings indicate that aged mouse ß cells compensate for the aging-induced alterations in the stimulus-secretion coupling, particularly by adjusting their Ca2+ influx to ensure insulin secretion. These results also suggest that decreased peripheral insulin sensitivity exacerbates the effects of aging on ß cells.

Coadministration of sitagliptin or metformin has no major impact on the adverse metabolic outcomes induced by dexamethasone treatment in rats.

AIMS: Glucocorticoids (GC) in excess cause glucose intolerance and dyslipidemia due to their diabetogenic actions. Conceptually, antidiabetic drugs should attenuate these side effects. Thus, we evaluated whether the coadministration of metformin or sitagliptin (or both) with dexamethasone could attenuate GC-induced adverse effects on metabolism. MATERIALS AND METHODS: Adult male rats were treated for 5 consecutive days with dexamethasone (1 mg/kg, body mass (bm), intraperitoneally). Additional groups were coadministered with metformin (300 mg/kg, bm, by oral gavage (og)) or sitagliptin (20 mg/kg, bm, og) or with both compounds in combination. The day after the last treatments, rats were submitted to glucose tolerance tests, pyruvate tolerance test, and euthanized for biometric, biochemical, morphologic, and molecular analyses. KEY FINDINGS: Dexamethasone treatment resulted in reduced body mass and food intake, increased blood glucose and plasma insulin, dyslipidemia, glucose intolerance, pyruvate intolerance, and increased hepatic content of glycogen and fat. Sitagliptin coadministration improved glucose tolerance compared with the control group, an effect paralleled with higher levels of active GLP-1 during an oral GTT. Overall, sitagliptin or metformin coadministration did not prevent any of the dexamethasone-induced metabolic disturbances. SIGNIFICANCE: Coadministration of sitagliptin or metformin result in no major improvement of glucose and lipid metabolism altered by dexamethasone treatment in male adult rats.

Excess of glucocorticoids during late gestation impairs the recovery of offspring's ß-cell function after a postnatal injury.

Since prenatal glucocorticoids (GC) excess increases the risk of metabolic dysfunctions in the offspring and its effect on ß-cell recovery capacity remains unknown we investigated these aspects in offspring from mice treated with dexamethasone (DEX) in the late pregnancy. Half of the pups were treated with streptozotocin (STZ) on the sixth postnatal day (PN). Functional and molecular analyses were performed in male offspring on PN25 and PN225. Prenatal DEX treatment resulted in low birth weight. At PN25, both the STZ-treated offspring developed hyperglycemia and had lower ß-cell mass, in parallel with higher α-cell mass and glucose intolerance, with no impact of prenatal DEX on such parameters. At PN225, the ß-cell mass was partially recovered in the STZ-treated mice, but they remained glucose-intolerant, irrespective of being insulin sensitive. Prenatal exposition to DEX predisposed adult offspring to sustained hyperglycemia and perturbed islet function (lower insulin and higher glucagon response to glucose) in parallel with exacerbated glucose intolerance. ß-cell-specific knockdown of the Hnf4α in mice from the DS group resulted in exacerbated glucose intolerance. We conclude that high GC exposure during the prenatal period exacerbates the metabolic dysfunctions in adult life of mice exposed to STZ early in life, resulting in a lesser ability to recover the islets' function over time. This study alerts to the importance of proper management of exogenous GCs during pregnancy and a healthy postnatal lifestyle since the combination of adverse factors during the prenatal and postnatal period accentuates the predisposition to metabolic disorders in adult life.

Maternal vitamin D administration attenuates metabolic disturbances induced by prenatal exposure to dexamethasone in a sex-dependent manner.

PURPOSE: The overexposure to synthetic glucocorticoids (GC) during pregnancy can predispose to metabolic diseases during adulthood. Vitamin D is not only crucial for fetal development, but also exerts direct effects on the GC sensitivity and down-regulates GC receptors. Given the vitamin D effects on glucocorticoid-related parameters, we aimed to investigate a possible protective role of maternal vitamin D administration on the glucose homeostasis of rats exposed to dexamethasone in utero. METHODS: Pregnant rats received dexamethasone (0.1 mg/kg, Dex) daily between the 14th and 19th days of pregnancy. A subgroup of dexamethasone-treated dams received oral administration of vitamin D (500UI, DexVD) during the whole gestation. The corresponding control groups of dams were included (CTL and VD groups, respectively). Male and female offspring were evaluated at 3, 6 and 12 months of age. RESULTS: Prenatal exposure to dexamethasone caused metabolic disruption in an age and sex-dependent manner being the older male offspring more susceptible to insulin resistance, fatty liver and beta-cell mass expansion than females. Furthermore, we demonstrated that prenatal GC led to glucose intolerance in male and female offspring in an age-dependent manner. Maternal vitamin D administration did not influence glucose intolerance but attenuated the insulin resistance, liver lipid accumulation and prevented the beta-cell mass expansion caused by prenatal dexamethasone in the male offspring. CONCLUSION: Maternal vitamin D administration mitigates metabolic disturbances that occur later in life in male rats exposed to GC in utero. Moreover, our data suggest vitamin D as an important nutritional supplement for pregnant overexposed to GC during gestation.

Reduced insulin sensitivity and increased ß/α cell mass is associated with reduced hepatic insulin-degrading enzyme activity in pregnant rats.

AIMS: Pregnancy is associated with the development of a transitory insulin resistance that parallels with the upregulation of pancreatic ß-cell function and mass. These metabolic adaptations guarantee the higher insulin demand, but there is no evidence of whether insulin clearance contributes to this process. Thus, we investigated some of the hepatic parameters related to insulin clearance during rat pregnancy. We also investigated some molecular parameters in the hypothalamus. MAIN METHODS: We evaluated the body mass and food intake, insulin sensitivity, ß- and α-cell masses, insulin clearance based on an exogenous insulin load, hepatic insulin-degrading enzyme (IDE) activity, and hepatic and hypothalamic protein content of IDE and carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM-1) in three periods of gestation in Wistar rats. KEY FINDINGS: In the first week of pregnancy, both insulin sensitivity and clearance increased, a pattern that inverted in the third week of gestation (reduced insulin sensitivity and clearance). Diminished insulin clearance was associated with lower hepatic IDE activity and higher pancreatic ß- and α-cell masses. No alteration in the hepatic IDE and CEACAM protein content was observed throughout pregnancy, but hypothalamic IDE protein content was significantly reduced in the late gestation period. SIGNIFICANCE: In conclusion, elevated insulin demand in the late period of gestation occurs not only as a result of increased ß-cell mass and function but also by a potential reduction in hepatic insulin clearance. Knowing this physiological process may be valuable when considering gestational diabetes mellitus results from a failure in insulin supply during pregnancy.

Impact of combined long-term fructose and prednisolone intake on glucose and lipid homeostasis in rats: benefits of intake interruption or fish oil administration.

We investigated whether combined long-term fructose and prednisolone intake would be more detrimental to the glucose homeostasis than if ingested separately. We also evaluated whether fish oil administration or interruption of treatments has any positive impact. For this, male adult Wistar rats ingested fructose (20%) (F) or prednisolone (12.5 µg/mL) (P) or both (FP) through drinking water for 12 weeks. A separate group of fructose and prednisolone-treated rats received fish oil treatment (1 g/kg) in the last 6 weeks. In another group, the treatment with fructose and prednisolone was interrupted after 12 weeks, and the animals were followed for more 12 weeks. Control groups ran in parallel (C). The F group had higher plasma TG (+42%) and visceral adiposity (+63%), whereas the P group had lower insulin sensitivity (-33%) and higher insulinemia (+200%). Only the the FP group developed these alterations combined with higher circulating uric acid (+126%), hepatic triacylglycerol content (+16.2-fold), lipid peroxidation (+173%) and lower catalase activity (-32%) that were associated with lower protein kinase B content and AMP-activated protein kinase (AMPK) phosphorylation in the liver, lower AMPK phosphorylation in the adipose tissue and higher beta-cell mass. Fish oil ingestion attenuated the elevation in circulating triacylglycerol and uric acid values, while the interruption of sugar and glucocorticoid intake reverted almost all modified parameters. In conclusion, long-term intake of fructose and prednisolone by male rats are more detrimental to glucose and lipid homeostasis than if ingested separately and the benefits of treatment interruption are broader than fish oil treatment.

COX-2 promotes mammary adipose tissue inflammation, local estrogen biosynthesis, and carcinogenesis in high-sugar/fat diet treated mice.

Obesity is a major risk factor for breast cancer, especially in post-menopausal women. In the breast tissue of obese women, cyclooxygenase-2 (COX-2)-dependent prostaglandin E2 (PGE2) production has been correlated with inflammation and local estrogen biosynthesis via aromatase. Using a mouse model of 7,12-dimethylbenz[a]anthracene/medroxyprogesterone-acetate (DMBA/MPA)-induced carcinogenesis, we demonstrated that an obesogenic diet promotes mammary tissue inflammation and local estrogen production, and accelerates mammary tumor formation in a COX-2-dependent manner. High-sugar/fat (HSF) diet augmented the levels of the pro-inflammatory mediators MCP-1, IL-6, COX-2, and PGE2 in mammary tissue, and this was accompanied by crown-like structures of breast (CLS-B) formation and aromatase/estrogen upregulation. Treatment with a COX-2 selective inhibitor, etoricoxib, decreased PGE2, IL-6, MCP-1, and CLS-B formation as well as reduced aromatase protein and estrogen levels in the mammary tissue of mice fed a HSF diet. Etoricoxib-treated mice showed increased latency and decreased incidence of mammary tumors, which resulted in prolonged animal survival when compared to HSF diet alone. Inhibition of tumor angiogenesis also seemed to account for the prolonged survival of COX-2 inhibitor-treated animals. In conclusion, obesogenic diet-induced COX-2 is sufficient to trigger inflammation, local estrogen biosynthesis, and mammary tumorigenesis.

Impact of different fructose concentrations on metabolic and behavioral parameters of male and female mice.

Clinical evidence has shown that a high consumption of sugar-sweetened beverages is a risk factor for developing obesity and metabolic syndrome. There has also been increasing interest in the potential effects of high-fructose intake on behavior. The present study evaluated sex differences in behavioral and metabolic characteristics in response to chronic fructose intake in mice. Swiss mice (3-months-old) had access to tap water or fructose-water solution (at 15% or 30% w/v) ad libitum for nine weeks. After the 8 weeks, the mice were submitted to a battery of behavioral tests. A glucose tolerance test was performed one day after these behavioral tests, and the next day blood was collected for biochemical analysis. At a 15% concentration, fructose-intaking resulted in higher plasma cholesterol levels and glucose intolerance in mice that paralleled with a passive stress-coping behavior in the female mice and lower self-care behavior in the male and the female mice. At a 30% concentration, fructose-intaking resulted in higher body mass gain and higher plasma cholesterol and triglycerides levels in the male and the female mice, whereas glucose intolerance was more pronounced in the male mice. Spatial memory impairments and lower self-care behavior were observed in the male and the female mice, while passive stress-coping behavior was observed only in the female mice. Collectively, high-fructose intake induces metabolic and behavioral alterations in mice, with the males being more susceptible to glucose metabolism dysfunctions and the females to depressive-like endophenotypes.

Gestational exposure to excessive levels of dexamethasone impairs maternal care and impacts on the offspring's survival in rats.

Administration of dexamethasone (DEX) during late gestation is a model to study growth restriction in rodents, but the pup's mortality index can be high, depending on DEX dosage, and little is known about the effects of DEX on maternal care (MC). Considering that an inadequate MC can also contribute to pup's mortality in this model, we evaluated the effects of DEX on dams' behavior and its consequences on offspring survival. We also investigated whether the cross-fostering of pups from dams treated or not with DEX could improve pup's survival. Wistar rats were treated with DEX (14th to 19th day of gestation -0.2 mg/kg, B.W, in the drinking water). Nest building, MC and responses in the elevated plus-maze, forced swimming and object recognition tests were evaluated. DEX reduced gestational weight gain and impaired neonatal development, reducing pup's survival to 0% by the 3rd postnatal day. DEX-treated dams reduced the expression of typical MC and increased anxiety-like behaviors. After cross-fostering, DEX-treated mothers behaved similarly to controls, indicating that a healthy offspring is crucial to induce adequate MC. Cross-fostering increased the survival index from zero to 25% in the DEX offspring. Postnatal development of the DEX offspring was comparable to controls after cross-fostering. We concluded that exposure to DEX during late gestation causes behavioral changes that compromise the maternal emotional state, disrupting the expression of MC. Although it does not seem to be the main cause of pup's mortality, our data indicate that an adequate MC improves pup's survival in this model.

Neonatal overnutrition programming impairs cholecystokinin effects in adultmale rats.

Overfeeding and rapid weight gain during early life are risk factors for the development of obesity in adulthood. This metabolic malprogramming may be mediated by endocrine disturbances during critical periods of development. Cholecystokinin (CCK) acts on the central nervous system by elevating thermogenesis and the activity of anorectic neurons, modulating overall energy balance. Therefore, we tested the hypothesis that postnatal overfeeding impaired CCK effects. Pups were raised in either a litter of three (neonatal overnutrition/small litter group) or 12 (controls/normal litter group) pups per dam to study the effects of postnatal overfeeding on the central and peripheral CCK systems in adulthood. Rats raised in small litters became overweight during lactation and remained overweight as adults, with increased adiposity and plasma levels of lipids, glucose, insulin, and leptin. Neonatally over-nourished rats showed attenuation of gastric emptying and anorexigenic response to CCK, suggesting that offspring from the SL group may present CCK resistance as adult male rats. Consistent with this idea, overweight rats displayed impaired central response in c-Fos immunoreactivity on the nucleus tractus solitarius, area postrema, paraventricular nucleus, central amygdala, arcuate nucleus, and dorsomedial hypothalamus in response to peripheral CCK at adulthood. The small litter group of adult male rats also exhibited reduced norepinephrine- and CCK-stimulated thermogenesis. Unresponsiveness to the effects of CCK may contribute to overweight and metabolic dysfunctions observed in postnatally over-nourished adult rats. Thus, the involvement of an impaired CCK system, among other neurohormonal failures, may contribute to the development of obesity.