Citrus aurantium L. and synephrine improve brown adipose tissue function in adolescent mice programmed by early postnatal overfeeding

Introduction and aims

Obesity is a multifactorial condition with high health risk, associated with important chronic disorders such as diabetes, dyslipidemia, and cardiovascular dysfunction. Citrus aurantium L. (C. aurantium) is a medicinal plant, and its active component, synephrine, a β-3 adrenergic agonist, can be used for weight loss. We investigated the effects of C. aurantium and synephrine in obese adolescent mice programmed by early postnatal overfeeding.

Methods

Three days after birth, male Swiss mice were divided into a small litter (SL) group (3 pups) and a normal litter (NL) group (9 pups). At 30 days old, SL and NL mice were treated with C. aurantium standardized to 6% synephrine, C. aurantium with 30% synephrine, isolated synephrine, or vehicle for 19 days.

Results

The SL group had a higher body weight than the NL group. Heart rate and blood pressure were not elevated. The SL group had hyperleptinemia and central obesity that were normalized by C. aurantium and synephrine. In brown adipose tissue, the SL group showed a higher lipid droplet sectional area, less nuclei, a reduction in thermogenesis markers related to thermogenesis (UCP-1, PRDM16, PGC-1α and PPARg), and mitochondrial disfunction. C. aurantium and synephrine treatment normalized these parameters.

Conclusion

Our data indicates that the treatment with C. aurantium and synephrine could be a promising alternative for the control of some obesity dysfunction, such as improvement of brown adipose tissue dysfunction and leptinemia.

Neonatal nicotine exposure affects adult rat hepatic pathways involved in endoplasmic reticulum stress and macroautophagy in a sex-dependent manner

Nonalcoholic fatty liver disease (NAFLD) involves changes in hepatic pathways, as lipogenesis, oxidative stress, endoplasmic reticulum (ER) stress, and macroautophagy. Maternal nicotine exposure exclusively during lactation leads to fatty liver (steatosis) only in the adult male offspring, not in females. Therefore, our hypothesis is that neonatal exposure to nicotine sex-dependently affects the signaling pathways involved in hepatic homeostasis of the offspring, explaining the hepatic lipid accumulation phenotype only in males. For this, between postnatal days 2 and 16, Wistar rat dams were implanted with osmotic minipumps, which released nicotine (NIC; 6 mg/Kg/day) or vehicle. The livers of offspring were evaluated at postnatal day 180. Only the male offspring that had been exposed to nicotine neonatally showed increased protein expression of markers of unfolded protein response (UPR), highlighting the presence of ER stress, as well as disruption of the activation of the macroautophagy repair pathway. These animals also had increased expression of diacylglycerol O-acyltransferase 1 and 4-hydroxynonenal, suggesting increased triglyceride esterification and oxidative stress. These parameters were not altered in the female offspring that had been neonatally exposed to nicotine, however they exhibited increased phospho adenosine monophosphate-activated protein kinase pAMPK expression, possibly as a protective mechanism. Thus, the disturbance in the hepatic homeostasis by UPR, macroautophagy, and oxidative stress modifications seem to be the molecular mechanisms underlying the liver steatosis in the adult male offspring of the nicotine-programming model. This highlights the importance of maternal smoking cessation during breastfeeding to decrease the risk of NAFLD development, especially in males.

Puberty as a DOHaD programming window: high-fat diet induces long-term hepatic dysfunction in male rats

The aim of this study was to evaluate whether high-fat (HF) diet intake during puberty can program obesity as well as generate glucose imbalance and hepatic metabolic dysfunctions in adult life. Male Wistar rats were randomly assigned into two groups: rats fed standard chow (NF) and rats fed a HF from postnatal 30-day-old (PND30) until PND60. Then, both groups were fed a standard chow from PND60 until PND120. Euthanasia and samples collections occurred at PND120. HF animals were overweight (+11%) and had increased adiposity, hyperphagia (+12%), hyperglycaemia (+13%), hyperinsulinemia (+69%), and hypertriglyceridemia (+34%). Plasma glucose levels during intravenous glucose tolerance test (ivGTT) and intraperitoneal insulin tolerance test (ipITT) were also higher in the HF group, whereas Kitt was significantly lower (-34%), suggesting reduced insulin sensitivity. In the same sense, HF animals present pancreatic islets hypertrophy and high β-cell mass. HF animals also had a significant increase in blood glucose levels during pyruvate tolerance test, indicating increased gluconeogenesis. Hepatic morphology analyses showed an increase in lipid inclusion in the HF group. Moreover, PEPCK and FAS protein expression were higher in the livers of the HF animals (+79% and + 37%, respectively). In conclusion, HF during puberty causes obese phenotype leading to glucose dyshomeostasis and nonalcoholic fatty liver disease, which can be related to the overexpression of proteins PEPCK and FAS.

Pesticides as endocrine disruptors: programming for obesity and diabetes

PURPOSE

Exposure to pesticides has been associated with obesity and diabetes in humans and experimental models mainly due to endocrine disruptor effects. First contact with environmental pesticides occurs during critical phases of life, such as gestation and lactation, which can lead to damage in central and peripheral tissues and subsequently programming disorders early and later in life.

METHODS

We reviewed epidemiological and experimental studies that associated pesticide exposure during gestation and lactation with programming obesity and diabetes in progeny.

RESULTS

Maternal exposure to organochlorine, organophosphate and neonicotinoids, which represent important pesticide groups, is related to reproductive and behavioral dysfunctions in offspring; however, few studies have focused on glucose metabolism and obesity as outcomes.

CONCLUSION

We provide an update regarding the use and metabolic impact of early pesticide exposure. Considering their bioaccumulation in soil, water, and food and through the food chain, pesticides should be considered a great risk factor for several diseases. Thus, it is urgent to reformulate regulatory actions to reduce the impact of pesticides on the health of future generations.

Adverse perinatal conditions and the developmental origins of thyroid dysfunction-Lessons from Animal Models

PURPOSE

Nutritional, hormonal, and environmental status during development can predispose the individual to obesity and endocrine diseases later in life, an association known as metabolic programming. In general, weight loss or gain are seen in thyroid disorders, and thyroid function can be affected by body adiposity. In addition, hyper- and hypothyroidism can be related to metabolic programming. Our aim was to gather evidence that regardless of the type or critical window of metabolic imprinting, offspring exposed to certain adverse perinatal conditions have a higher risk of developing thyroid dysfunction.

METHODS

We reviewed literature data that relate insults occurring during pregnancy and/or lactation to short- and long-term offspring thyroid dysfunction in animal models.

RESULTS

Few studies have addressed the hypothalamic-pituitary-thyroid axis and thyroid dysfunction related to metabolic programming. The literature shows that under- and overnutrition, exposure to endocrine disruptors, early weaning, maternal thyroid disease and maternal high-fat diet can induce alterations in offspring thyroid function in a sex-dependent manner.

CONCLUSION

Based on the few available data, mainly in rodent models, we can conclude that diet, hormones, and environmental contaminants are related to the developmental origins of later thyroid dysfunction by interrupting the normal maturation of the thyroid gland.

Human exposure to bisphenol A (BPA) through medical-hospital devices: A systematic review

This systematic review explored the literature pertaining to patient exposure to bisphenol A (BPA) through medical-hospital devices. The acronym PICO: Patient (Medical-hospital devices), Intervention/Exposure (Bisphenol A), Comparison (Different grades of exposure) and Outcome (Assessment of exposure levels) was used. The databases used were LILACS, IBECS, MEDLINE, Capes Journal Portal, Food Science Source, FSTA and CINAHL with Full Text from EBSCO, Embase and Scopus by Elsevier, Web of Science and SCIELO. A total of 9747 references were found. After removing duplicate records, 7129 studies remained. After applying exclusion criteria and qualitative analysis, 12 articles remained. Studies have shown associations between the use of medical-hospital devices and patients' exposure to BPA. For chronic renal patients, there was an association between plasma BPA and disease severity. This review identifies that exposure to BPA is increased after the use of medical-hospital devices. More studies that address the clinical outcome of patients exposed to medical-hospital materials containing BPA are needed.

Low protein diet during lactation programs hepatic metabolism in adult male and female rats

The liver is an essential regulator of energy metabolism, and its function can be disrupted by nutritional alterations. Since liver development continues during breastfeeding nutritional challenges during this period predispose patients to diseases throughout life. A maternal protein-restricted (PR) diet during lactation promotes reductions in the body weight, adiposity, and plasma glucose and insulin, leptin resistance and an increase in corticosterone and catecholamines in adult male rat offspring. Here, we investigated hepatic metabolism in the offspring (both sexes) of PR (8% protein diet during lactation) and control (23% protein diet) dams. Both male and female offspring were evaluated at 6 months of age. PR males had no liver steatosis and manifested a reduction in lipids in hepatocytes adjacent to the vasculature. These animals had lower levels of esterified cholesterol in hepatocytes, suggesting higher biliary excretion, unchanged glycolysis and gluconeogenesis, and lower contents of the markers of mitochondrial redox balance and endoplasmic reticulum (ER) stress response and estrogen receptor alpha. PR females showed normal hepatic morphology associated with higher uptake of cholesterol esters, normal glycolysis and gluconeogenesis, and lower ER stress parameters without changes in the key markers of the redox balance. Additionally, these animals had lower content of estrogen receptor alpha and higher content of androgen receptor. The maternal PR diet during lactation did not program hepatic lipid accumulation in the adult progeny. However, several repair homeostasis pathways were altered in males and females, possibly compromising maintenance of normal liver function.

Changes in gut-brain axis parameters in adult rats of both sexes with different feeding pattern that were early nicotine-exposed

Nicotine is an endocrine disruptor and imprinting factor during breastfeeding that can cause food intake imbalance in the adulthood. As nicotine affects the intestinal microbiota, altering the composition of the bacterial communities and short-chain fatty acids (SCFAs) synthesis in a sex-dependent manner, we hypothesized that nicotine could program the gut-brain axis, consequently modifying the eating pattern of adult male and female rats in a model of maternal nicotine exposure (MNE) during breastfeeding. Lactating Wistar rat dams received minipumps that release 6 mg/kg/day of nicotine (MNE group) or saline for 14 days. The progeny received standard diet from weaning until euthanasia (26 weeks of age). We measured: in vivo electrical activity of the vagus nerve; c-Fos expression in the nucleus tractus solitarius, gastrointestinal peptides receptors, intestinal brain-derived neurotrophic factor (BDNF), SCFAs and microbiota. MNE females showed hyperphagia despite normal adiposity, while MNE males had unchanged food intake, despite obesity. Adult MNE offspring showed decreased Bacteroidetes and increased Firmicutes, Actinobacteria and Proteobacteria. MNE females had lower fecal acetate while MNE males showed higher vagus nerve activity. In summary nicotine exposure through the milk induces long-term intestinal dysbiosis, which may affect eating patterns of adult offspring in a sex-dependent manner.

Breastfeeding undernutrition changes iBAT-involved thermogenesis protein expression and leads to a lean phenotype in adult rat offspring

Nutritional insults early in life have been associated with metabolic diseases in adulthood. We aimed to evaluate the effects of maternal food restriction during the suckling period on metabolism and interscapular brown adipose tissue (iBAT) thermogenically involved proteins in adult rat offspring. Wistar rats underwent food restriction by 50% during the first two-thirds of lactation (FR50 group). Control rats were fed ad libitum throughout lactation (CONT group). At birth, the litter size was adjusted to eight pups, and weaning was performed at 22 days old. Body weight and food and water intake were assessed every two days. High- (HCD, 4,589 cal) and normal-caloric diet (NCD, 3,860 cal) preferences, as well as food intake during the dark part of the cycle, were assessed. At 100 days old, the rats were euthanized, and blood and tissues were removed for further analyses. Adult FR50 rats, although hyperphagic and preferring to eat HCD (P<.001), were leaner (P<.001) than the CONT group. The FR50 rats, were normoglycemic (P=.962) and had hypertriglyceridemia (P<.01). In addition, the FR50 rats were dyslipidemic (P<.01), presenting with a high atherogenic risk by the Castelli indexes (P<.01), had a higher iBAT mass (P<.01), fewer β₃ adrenergic receptors (β₃-AR, P<.05) and higher iBAT expression of uncoupled protein 1 (UCP1, P<.05) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α, P<.001) than the CONT rats. In conclusion, maternal food restriction during early breastfeeding programs rat offspring to have a lean phenotype, despite hyperphagia, and increased iBAT UCP1 and PGC-1α protein expression.

Germinated millet flour (Pennisetum glaucum (L.) R. BR.) improves adipogenesis and glucose metabolism and maintains thyroid function in vivo

This study investigated the effects of germinated millet flour on adipogenesis, insulin resistance, glucose tolerance and thyroid function in Wistar rats fed with a high-fat high-fructose diet (HFHF). The experiment was divided into two phases. Phase 1: control group, which received an AIN-93M diet (n = 10) and HFHF group (n = 20), which received a diet rich in saturated fat (31%) and fructose (20%), for eight weeks. Phase 2: intervention: the control group maintained the AIN-93M diet (n = 10) and the HFHF group was divided into two groups: the HFHF (n = 10) and the germinated millet group (n = 10), for 10 weeks. The germinated millet flour maintained (p > 0, 05) the plasma levels of thyroid hormones, increased (p < 0.05) the insulin receptor (INSR) mRNA expression, protein kinase B (AKT) mRNA expression and the phospho-AKT1 protein concentration, phosphofructokinase (PFK) mRNA, pyruvate kinase (PK) mRNA and activated protein kinase (AMPK) mRNA expression, and the brown adipose tissue and reduced (p < 0.05) the glucose triglyceride index (TyG), glucose, insulin, HOMA-IR and hypercorticosteronemia, compared to the HFHF group. These effects contributed to reduce the gluconeogenesis, hyperinsulinemia and adiposity. Thus, germinated millet flour is a good alternative for modulating the adipogenesis and glucose metabolism, without interfering with the thyroid hormones, in rats with an insulin resistance condition with a high-fat high-fructose diet.

The Role of Fatty Acids in Ceramide Pathways and Their Influence on Hypothalamic Regulation of Energy Balance: A Systematic Review

Obesity is a global health issue for which no major effective treatments have been well established. High-fat diet consumption is closely related to the development of obesity because it negatively modulates the hypothalamic control of food intake due to metaflammation and lipotoxicity. The use of animal models, such as rodents, in conjunction with in vitro models of hypothalamic cells, can enhance the understanding of hypothalamic functions related to the control of energy balance, thereby providing knowledge about the impact of diet on the hypothalamus, in addition to targets for the development of new drugs that can be used in humans to decrease body weight. Recently, sphingolipids were described as having a lipotoxic effect in peripheral tissues and the central nervous system. Specifically, lipid overload, mainly from long-chain saturated fatty acids, such as palmitate, leads to excessive ceramide levels that can be sensed by the hypothalamus, triggering the dysregulation of energy balance control. However, no systematic review has been undertaken regarding studies of sphingolipids, particularly ceramide and sphingosine-1-phosphate (S1P), the hypothalamus, and obesity. This review confirms that ceramides are associated with hypothalamic dysfunction in response to metaflammation, endoplasmic reticulum (ER) stress, and lipotoxicity, leading to insulin/leptin resistance. However, in contrast to ceramide, S1P appears to be a central satiety factor in the hypothalamus. Thus, our work describes current evidence related to sphingolipids and their role in hypothalamic energy balance control. Hypothetically, the manipulation of sphingolipid levels could be useful in enabling clinicians to treat obesity, particularly by decreasing ceramide levels and the inflammation/endoplasmic reticulum stress induced in response to overfeeding with saturated fatty acids.

Pancreatic steatosis in adult rats induced by nicotine exposure during breastfeeding

PURPOSE

Maternal nicotine exposure negatively impacts offspring's health and metabolism, leading to obesity and insulin resistance. Here we investigated the pancreatic islet function, glycemic homeostasis, and insulin signaling in adult rat offspring that were nicotine-exposed during breastfeeding.

METHODS

For this, lactating Wistar rat dams were divided into two groups: Nicotine (implanted with osmotic minipumps containing 6 mg/Kg, NIC) and Control (saline, CON). Solutions were released from postnatal (PN) day 2-16. At PN110 and PN170, 10 offspring per litter/sex/group were submitted to the oral glucose tolerance test (OGTT). PN180 offspring were killed and glycemia, insulinemia, adiponectinemia, pancreas morphology as well as pancreatic islet protein expression (related to insulin secretion) and skeletal muscle (related to insulin action) were evaluated. Males and females were compared to their respective controls.

RESULTS

Adult NIC offspring of both sexes showed glucose intolerance in the OGTT. Despite normoglycemia, NIC males showed hyperinsulinemia while females, although normoinsulinemic, had hyperglycemia. Both sexes showed increased IRI, reduced adiponectin/visceral fat mass ratio and higher ectopic deposition of lipids in the pancreatic tissue adipocytes. In pancreatic islets, NIC males showed lower PDX-1 expression while females had higher PDX-1 and GLUT2 expressions plus lower α2 adrenergic receptor. In the muscle, NIC offspring of both sexes showed reduction of GLUT4 expression; NIC males also had lower insulin receptor and pAKT expressions.

CONCLUSIONS

Thus, glycemic homeostasis and peripheral insulin signaling in adult offspring of both sexes are affected by nicotine exposure through the milk, increasing the risk for type 2 diabetes development.

Nicotine exposure during lactation causes disruption of hedonic eating behavior and alters dopaminergic system in adult female rats

Tobacco smoke during gestation is associated with increased consumption of palatable foods by the offspring in humans and rats. Postpartum relapse is observed in lactating women who quit smoking during pregnancy, putting their children at risk of adverse health outcomes caused by secondhand smoke. Nicotine is transferred through milk and alters the dopaminergic reward system of adult male rats, reducing dopamine action in the nucleus accumbens (NAc) and hypothalamic arcuate nucleus. Here, we evaluated the long-term effects of nicotine-only exposure during lactation on eating behavior, anxiety, locomotion, dopaminergic system, hypothalamic leptin signaling and nicotinic receptor in the adult female rat progeny. Two days after birth (PN2), Wistar rat dams were separated into control and nicotine (Nic) groups for implantation of osmotic minipumps that released respectively saline or 6 mg/kg nicotine. Lactating dams were kept with 6 pups. After weaning (PN21; nicotine withdrawal), only the female offspring were studied. Euthanasia occurred at PN180. Nic females showed hyperphagia, preference for a high-sucrose diet, increased anxiety-like behavior, lower tyrosine hydroxylase (TH), lower dopamine transporter and higher dopamine receptor (Drd2) in NAc; lower Drd1 in prefrontal cortex and lower TH in dorsal striatum (DS). These animals showed changes that can explain their hyperphagia, such as: lower leptin signaling pathway (Lepr^b, pJAK2, pSTAT3) and Chrna7 expression in hypothalamus. Neonatal nicotine exposure affects the brain reward system of the female progeny differently from males, mainly decreasing dopamine production in NAc and DS. Therefore, Nic females are more susceptible to develop food addiction and obesity.

Protein restriction during pregnancy impairs intra-islet GLP-1 and the expansion of β-cell mass

We evaluated whether protein restriction during pregnancy alters the morphometry of pancreatic islets, the intra-islet glucagon-like peptide-1 (GLP-1) production, and the anti-apoptotic signalling pathway modulated by GLP-1. Control non-pregnant (CNP) and control pregnant (CP) rats were fed a 17% protein diet, and low-protein non-pregnant (LPNP) and low-protein pregnant (LPP) groups were fed a 6% protein diet. The masses of islets and β-cells were similar in the LPNP group and the CNP group but were higher in the CP group than in the CNP group and were equal in the LPP group and the LPNP group. Both variables were lower in the LPP group than in the CP group. Prohormone convertase 2 and GLP-1 fluorescence in α-cells was lower in the low-protein groups than in the control groups. The least PC2/glucagon colocalization was observed in the LPP group, and the most was observed in the CP group. There was less prohormone convertase 1/3/glucagon colocalization in the LPP group than in the CP group. GLP-1/glucagon colocalization was similar in the LPP, CP and CNP groups, which showed less GLP-1/glucagon colocalization than the LPNP group. The mRNA Pka, Creb and Pdx-1 contents were higher in islets from pregnant rats than in islets from non-pregnant rats. Protein restriction during pregnancy impaired the mass of β-cells and the intra-islet GLP-1 production but did not interfere with the transcription of genes of the anti-apoptotic signalling pathway modulated by GLP-1.

Tobacco smoking during breastfeeding increases the risk of developing metabolic syndrome in adulthood: Lessons from experimental models

Metabolic syndrome (MetS) is characterized by increased abdominal fat, dyslipidemia, diabetes mellitus and hypertension. A high MetS prevalence is strongly associated with obesity. Obesity is a public health problem in which several complex factors have been implicated, including environmental pollutants. For instance, maternal smoking seems to play a role in obesogenesis in childhood. Given the association between endocrine disruptors, obesity and metabolic programming, over the past 10 years, our research group has contributed to studies based on the hypothesis that early exposure to nicotine/tobacco causes offspring to become MetS-prone. The mechanism by which tobacco smoking during breastfeeding induces metabolic dysfunctions is not completely understood; however, increased metabolic programming has been shown in studies that focus on this topic. Here, we reviewed the literature mainly based in light of our latest data from experimental models. Nicotine or tobacco exposure during breastfeeding induces several endocrine dysfunctions in a sex- and tissue-specific manner. This review provides an updated summary regarding the hypothesis that early exposure to nicotine/tobacco causes offspring to become MetS-prone. An understanding of this issue can provide support to prevent long-term disorders, mainly related to the risk of obesity and its comorbidities, in future generations.

Maternal soy protein isolate diet during lactation programmes to higher metabolic risk in adult male offspring

Soy consumption and its components, including its protein, are related to the beneficial effects of the lipid profile, decreased insulin resistance and glycaemia. However, the safety of the consumption of products containing phytoestrogens in critical stages of development has been questioned, since they may be associated with endocrine-metabolic dysfunctions in adult life. The purpose is to evaluate the effects of maternal dietary soy protein isolate (SPI) during lactation on the breast milk composition, body composition, lipid and glycaemic profiles, and thyroid hormones of dams and offspring at weaning (21 days) and in adulthood (150 days). Lactating rats were divided into casein control (C) and SPI diet groups. At 150 days, the SPI offspring presented lower body protein mass and total mineral content, higher serum FT4, insulin, TC and TG. Maternal consumption of SPI during lactation programmes the progeny to higher metabolic risk profile.

Programming of hepatic lipid metabolism in a rat model of postnatal nicotine exposure - Sex-related differences

Maternal nicotine exposure during lactation induces liver damage in adult male rats. However, the mechanism in males is unknown and females have not been tested. Here, we determined the liver lipid composition and lipogenic enzymes in male and female offspring at two ages in a model of postnatal nicotine exposure. Osmotic minipumps were implanted in lactating Wistar rat dams at postnatal day (PND) 2 to release 6 mg/kg/day of nicotine (NIC group) or saline (CON group) for 14 days. Offspring received a standard diet from weaning until euthanasia at PND120 (1 pup/litter/sex) or PND180 (2 pups/litter/sex). At PND120, NIC males showed lower plasma triglycerides (TG), steatosis degree 1, higher hepatic cholesterol (CHOL) ester, free fatty acids, monoacylglycerol content as well as acetyl-coa carboxylase-1 (ACC-1) and fatty acid synthase (FAS) protein expression in the liver compared to CON males. At this age, NIC females had preserved hepatocytes architecture, higher plasma CHOL, higher CHOL ester and lower total CHOL content in the liver compared to CON females. At PND180, NIC males showed steatosis degrees 1 and 2, higher TG, lower free fatty acids and total CHOL content in the liver and an increase in ACC-1 hepatic protein expression. NIC females had higher plasma TG and CHOL levels, no change in hepatic morphology, lower CHOL ester and free fatty acids in the liver, which also showed higher total ACC-1 and FAS protein expression. Maternal nicotine exposure induces long-term liver dysfunction, with an alteration in hepatic cytoarchitecture that was aggravated with age in males. Concerning females, despite unchanged hepatic cytoarchitecture, lipid metabolism was compromised, which deserves further attention.

Early weaning induces short- and long-term effects on pancreatic islets in Wistar rats of both sexes

KEY POINTS

The World Health Organization recommends exclusive breastfeeding until 6 months of age as an important strategy to reduce child morbidity and mortality. Studies have associated early weaning with the development of obesity and type 2 diabetes in adulthood. In our model, we demonstrated that early weaning leads to increased insulin secretion in adolescent males and reduced insulin secretion in adult offspring. Early weaned males exhibit insulin resistance in skeletal muscle. Early weaning did not change insulin signalling in the muscle of female offspring. Taking into account that insulin resistance is one of the primary factors for the development of type 2 diabetes mellitus, this work demonstrates the importance of breastfeeding in the fight against this disease.

ABSTRACT

Early weaning (EW) leads to short- and long-term obesity and diabetes. This phenotype is also observed in experimental models, in which early-weaned males exhibit abnormal insulinaemia in adulthood. However, studies regarding the effect of EW on pancreatic islets are rare. We investigated the mechanisms by which glycaemic homeostasis is altered in EW models through evaluations of insulin secretion and its signalling pathway in offspring. Lactating Wistar rats and their pups were divided into the following groups: non-pharmacological EW (NPEW): mothers were wrapped with an adhesive bandage on the last 3 days of lactation; pharmacological EW (PEW): mothers received bromocriptine to inhibit prolactin (1 mg/kg body mass/day) on the last 3 days of lactation; and control (C): pups underwent standard weaning at PN21. Offspring of both sexes were euthanized at PN45 and PN180. At PN45, EW males showed higher insulin secretion (vs. C). At PN170, PEW males exhibited hyperglycaemia in an oral glucose tolerance test (vs. C and NPEW). At PN180, EW male offspring were heavier; however, both sexes showed higher visceral fat. Insulin secretion was lower in EW offspring of both sexes. Males from both EW groups had lower glucokinase in islets, but unexpectedly, PEW males showed higher GLUT2, than did C. EW males exhibited lower insulin signalling in muscle. EW females exhibited no changes in these parameters compared with C. We demonstrated distinct alterations in the insulin secretion of EW rats at different ages. Despite the sex dimorphism in insulin secretion in adolescence, both sexes showed impaired insulin secretion in adulthood due to EW.

Hypothalamic Neuropeptides Expression and Hypothalamic Inflammation in Adult Rats that Were Exposed to Tobacco Smoke during Breastfeeding: Sex-Related Differences

The hypothalamus controls food intake and energy expenditure. In rats, maternal exposure to nicotine during breastfeeding alters the hypothalamic circuitry of the adult offspring, resulting in leptin resistance, neuropeptides changes and gliosis. Tobacco smoke exposure during lactation causes greater adiposity, hyperphagia and hyperleptinemia in the adult progeny. To understand the central mechanisms underlying the obese phenotype of adult rats that were directly and indirectly exposed to cigarette smoke during lactation, we investigated leptin signaling, orexigenic and anorexigenic neuropeptides expression, as well as astrocyte and microglia markers in hypothalamus. From postnatal day (PND) 3 to 21, Wistar lactating rat dams and their pups were divided into two groups: SE, smoke-exposed in a cigarette-smoking machine (four times/day); Crtl, exposed to filtered air. Offspring of both sexes were euthanized at PND180. The leptin pathway was not altered in SE animals from both sexes. SE males showed increased NPY (arcuate nucleus, ARC), CRH (paraventricular nucleus, PVN), as well as higher GFAP fiber density (ARC and PVN) and IL6 protein content. TRH (PVN) immunohistochemistry was reduced. SE females had lower CART-positive cells (ARC) and lower α-MSH immunostaining intensity (PVN and lateral hypothalamus), with no change of GFAP or IL-6. The protein contents of CX3CR1 (marker of activated microglia) and α7nAChR (anti-inflammatory marker) were not altered in both SE males and females. Neonatal cigarette smoke is deleterious to the hypothalamic circuitry, inducing changes in energy homeostasis favoring hyperphagia and decreased energy expenditure at adulthood in both sexes; however sex-dependent mechanisms were observed.

Cigarette smoke during lactation in rat female progeny: Late effects on endocannabinoid and dopaminergic systems

AIMS

Maternal smoking is considered a risk factor for childhood obesity. In a rat model of tobacco exposure during breastfeeding, we previously reported hyperphagia, overweight, increased visceral fat and hyperleptinemia in adult female offspring. Obesity and eating disorders are associated with impairment in the endocannabinoid (EC) and dopaminergic (DA) systems. Considering that women are prone to eating disorders, we hypothesize that adult female Wistar rats that were exposed to cigarette smoke (CS) during the suckling period would develop EC and DA systems deregulation, possibly explaining the eating disorder in this model.

MATERIAL AND METHODS

To mimic maternal smoking, from postnatal day 3 to 21, dams and offspring were exposed to a smoking machine, 4×/day/1 h (CS group). Control animals were exposed to ambient air. Offspring were evaluated at 26 weeks of age.

KEY FINDINGS

Concerning the EC system, the CS group had increased expression of diacylglycerol lipase (DAGL) in the lateral hypothalamus (LH) and decreased in the liver. In the visceral adipose tissue, the EC receptor (CB1r) was decreased. Regarding the DA system, the CS group showed higher dopamine transporter (DAT) protein expression in the prefrontal cortex (PFC) and lower DA receptor (D2r) in the arcuate nucleus (ARC). We also assessed the hypothalamic leptin signaling, which was shown to be unchanged. CS offspring showed decreased plasma 17β-estradiol.

SIGNIFICANCE

Neonatal CS exposure induces changes in some biomarkers of the EC and DA systems, which can partially explain the hyperphagia observed in female rats.

Early weaning alters the thermogenic capacity of brown adipose tissue in adult male and female rats

PURPOSE

Early weaning (EW) is a risk factor for obesity development. Brown adipose tissue (BAT) hypofunction is related to obesity onset. Here, we evaluated whether sympathetic nervous system (SNS) activity in BAT and the thermogenic function of BAT are decreased in adulthood in obese rats from two EW models.

METHODS

At the time of birth, lactating Wistar rats and their pups (three males and three females) were separated into three groups: the control group, in which pups consumed milk throughout lactation; the non-pharmacological EW (NPEW) group, in which suckling was interrupted with a bandage during the last 3 days of lactation; and the pharmacological EW (PEW) group, in which dams were treated with bromocriptine (0.5 mg/twice a day) 3 days before weaning. The offspring were sacrificed on PN180.

RESULTS

Adult male rats from both EW models exhibited lower BAT SNS activity. Female rats from the PEW group showed a decrease in BAT SNS activity. The protein levels of UCP1 were lower in the NPEW males, while PGC1α levels were lower in both PEW and NPEW males. Both groups of EW females showed reductions in the levels of β3-AR, TRβ1, and PGC1α. The UCP1 protein level was reduced only in the NPEW females. The EW groups of both sexes had lower AMPK protein levels in BAT. In the hypothalamus, only the PEW females showed an increase in AMPK protein levels. In both groups of EW males, adrenal catecholamine was increased and tyrosine hydroxylase was decreased, while in EW females, adrenal catecholamine was decreased.

CONCLUSIONS

Early weaning alters the thermogenic capacity of BAT, which partially contributes to obesity in adulthood, and there are sex-related differences in these alterations.

Short and long-term effects of bisphenol S (BPS) exposure during pregnancy and lactation on plasma lipids, hormones, and behavior in rats

Bisphenol S (BPS) has replaced bisphenol A (BPA), a known non-persistent endocrine disrupting chemical, in several products. Considering that little is known regarding BPS effects, especially during critical windows of ontogenetic development, and that BPA, which is quite similar to BPS, is know to be transferred to the offspring via the placenta and milk, in the present study we investigated the behavioral, biochemical and endocrine profiles of Wistar rats born from dams that were BPS-exposed [groups: BPS10 (10 μg/kg/day), BPS50 (50 μg/kg/day)] during pregnancy and lactation. Due to the non-monotonic dose-response effect of bisphenol, the data of both BPS groups were directly compared with those of the controls, not to each other. Males and females were analyzed separately. At weaning, male BPS50 offspring had hypotriglyceridemia and hyperthyroxinemia, whereas BPS50 females showed higher 25(OH)D levels. At adulthood, BPS offspring of both sexes had lower food intake. BPS males showed lower visceral adiposity. BPS50 females had smaller fat droplets in brown adipocytes. BPS males showed higher anxiety and higher locomotor activity, while BPS10 females showed lower exploration. During a food challenge test at adulthood, BPS males consumed more high-fat diet at 30 min. BPS10 females initially (at 30 min) consumed more high-fat diet but, after 12 h, less of this diet was consumed. BPS50 males had hypertriglyceridemia and lower plasma T3, while BPS females showed lower plasma T4. BPS10 females had lower progesterone, whereas BPS50 females had higher plasma 25(OH)D. Maternal BPS exposure has adverse effects on the triacylglycerol, hormones levels and behavior of the progeny. Furthermore, the increased preference for the fat-enriched diet suggests an increased risk for obesity and its health consequences in the long term.

Monosodium l-glutamate-obesity onset is associated with disruption of central control of the hypothalamic-pituitary-adrenal axis and autonomic nervous system

The hypothalamic-pituitary-adrenal axis (HPA) exerts important catabolic peripheral effects and influences autonomic nervous system (ANS)-mediated processes. Impaired negative-feedback control or reduced HPA axis sensitivity and altered ANS activity appear to be associated with the development and maintenance of obesity. In the present study, we examined the hypothesis that the central HPA axis is dysregulated favouring ANS disbalance in monosodium l-glutamate (MSG)-induced rat obesity. Glucose homeostasis, corticosterone, leptin and ANS electrical activity were evaluated. Adult MSG-induced obese rats exhibited fasting hyperinsulinaemia, insulin resistance, glucose intolerance, hypercorticosteronaemia, hyperleptinaemia and altered ANS activity. A decrease in food intake was observed during corticotrophin-releasing hormone (CRH) treatment in both control and MSG-treated rats. By contrast, food intake was significantly elevated in control rats treated with dexamethasone (DEXA), whereas no alterations were observed following DEXA treatment in MSG-induced obese rats. After DEXA injection, an increase in fasting insulin and glucose levels, associated with insulin resistance, was seen in both groups. As expected, there was a decrease of parasympathetic activity and an increase of sympathetic nervous activity in CRH-treated control animals and the opposite effect was seen after DEXA treatment. By contrast, there was no effect on ANS activity in MSG-rats treated with CRH or DEXA. In conclusion, impairment of the HPA axis can lead to disbalance of ANS activity in MSG-treated rats, contributing to the establishment and maintenance of obesity.

Low-protein diet in puberty impairs testosterone output and energy metabolism in male rats

We examined the long-term effects of protein restriction during puberty on the function of hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes in male rats. Male Wistar rats from the age of 30 to 60 days were fed a low-protein diet (4%, LP). A normal-protein diet (20.5%) was reintroduced to rats from the age of 60 to 120 days. Control rats were fed a normal-protein diet throughout life (NP). Rats of 60 or 120 days old were killed. Food consumption, body weight, visceral fat deposits, lipid profile, glycemia, insulinemia, corticosteronemia, adrenocorticotropic hormone (ACTH), testosteronemia and leptinemia were evaluated. Glucose-insulin homeostasis, pancreatic-islet insulinotropic response, testosterone production and hypothalamic protein expression of the androgen receptor (AR), glucocorticoid receptor (GR) and leptin signaling pathway were also determined. LP rats were hypophagic, leaner, hypoglycemic, hypoinsulinemic and hypoleptinemic at the age of 60 days (P < 0.05). These rats exhibited hyperactivity of the HPA axis, hypoactivity of the HPG axis and a weak insulinotropic response (P < 0.01). LP rats at the age of 120 days were hyperphagic and exhibited higher visceral fat accumulation, hyperleptinemia and dyslipidemia; lower blood ACTH, testosterone and testosterone release; and reduced hypothalamic expression of AR, GR and SOCS3, with a higher pSTAT3/STAT3 ratio (P < 0.05). Glucose-insulin homeostasis was disrupted and associated with hyperglycemia, hyperinsulinemia and increased insulinotropic response of the pancreatic islets. The cholinergic and glucose pancreatic-islet responses were small in 60-day-old LP rats but increased in 120-day-old LP rats. The hyperactivity of the HPA axis and the suppression of the HPG axis caused by protein restriction at puberty contributed to energy and metabolic disorders as long-term consequences.

Treatment with Ilex paraguariensis (yerba mate) aqueous solution prevents hepatic redox imbalance, elevated triglycerides, and microsteatosis in overweight adult rats that were precociously weaned

Early weaning (EW) leads to overweight, visceral obesity, hyperleptinemia, and insulin resistance in adulthood. Treatment with Ilex paraguariensis (yerba mate) improves obesity and insulin resistance in these animals. Here, we evaluated the effects of chronic treatment with yerba mate on the redox balance and liver morphology of overweight early-weaned rats. To induce EW, we wrapped the dams with bandages to interrupt milk access during the last 3 days of lactation. Control pups (C) had free access to maternal milk for the full 21 days of lactation. On postnatal day (PN) 150, EW offspring were subdivided into the EW+YM group, which received the aqueous extract of yerba mate (1 g/kg bw by gavage once a day for 30 days) and the EW group, which received water by gavage for the same period. All rats were euthanized on PN180. The EW group showed higher bound carbonyl (a marker of total protein oxidation), higher TBARS levels (a marker of lipid peroxidation), and lower superoxide dismutase (SOD) activity in liver tissue than the C group, as well as higher triglyceride content and microsteatosis. In plasma, the EW offspring showed higher TBARS levels. One month of yerba mate treatment normalized these parameters. Thus, we have shown evidence that yerba mate improved antioxidant defenses and mitigated liver dysfunction in overweight adult rats that were weaned prematurely.

Maternal soybean diet during lactation alters breast milk composition and programs the lipid profile in adult male rat offspring

PURPOSE

To evaluate the effects of maternal dietary soybean during lactation on the milk composition, body composition, lipid profile and glucose homeostasis of dams and offspring at weaning (21 days) and adulthood (150 days).

METHODS

Lactating rats were divided into: casein control (C): casein diet; soy (S): soybean diet; soy oil control (SOC): casein diet, but with fat content similar to the S group.

RESULTS

At 21 days, S mothers showed lower estradiol, total cholesterol (TC), low-density lipoprotein cholesterol (LDL) and triglycerides (TG) in serum; and lower TC and TG in milk. The S offspring had lower body weight, body fat mass, TC, LDL, hyperleptinemia and hypertriglyceridemia. At 150 days, S offspring presented higher total mineral content and lower TC (v. SOC) and LDL (v. C and SOC), and hyperinsulinemia with lower glycemia v. SOC group, which had lower insulinemia with higher glycemia, TC and LDL.

CONCLUSIONS

Maternal intake of soybeans in lactation changes the lipid content of breast milk and programmed offspring for phenotype of the lower metabolic risk, with lower serum TC and LDL, and seems to protect the progeny of alterations in glucose metabolism despite the higher lipid content. The difference in fat content of breast milk and the higher isoflavones content of soy diet are possible imprinting factors that could program the offspring.

Neonatal tobacco smoke reduces thermogenesis capacity in brown adipose tissue in adult rats

Maternal smoking is a risk factor for progeny obesity. We have previously shown, in a rat model of neonatal tobacco smoke exposure, a mild increase in food intake and a considerable increase in visceral adiposity in the adult offspring. Males also had secondary hyperthyroidism, while females had only higher T4. Since brown adipose tissue (BAT) hypofunction is related to obesity, here we tested the hypothesis that higher levels of thyroid hormones are not functional in BAT, suggesting a lower metabolic rate. We evaluated autonomic nerve activity in BAT and its function in adult rats that were exposed to tobacco smoke during lactation. At birth, litters were adjusted to 3 male and 3 female pups/litter. From postnatal day (PND) 3 to 21, Wistar lactating rats and their pups were divided into SE group, smoke-exposed in a cigarette smoking machine (4 times/day) and C group, exposed to filtered air. Offspring were sacrificed at PND180. Adult SE rats of both genders had lower interscapular BAT autonomic nervous system activity, with higher BAT mass but no change in morphology. BAT UCP1 and CPT1a protein levels were decreased in the SE groups of both genders. Male SE rats had lower β3-AR, TRα1, and TRβ1 expression while females showed lower PGC1α expression. BAT Dio2 mRNA and hypothalamic POMC and MC4R levels were similar between groups. Hypothalamic pAMPK level was higher in SE males and lower in SE females. Thus, neonatal cigarette smoke exposure induces lower BAT thermogenic capacity, which can be obesogenic at adulthood.

Cross-fostering reduces obesity induced by early exposure to monosodium glutamate in male rats

Maternal obesity programmes a range of metabolic disturbances for the offspring later in life. Moreover, environmental changes during the suckling period can influence offspring development. Because both periods significantly affect long-term metabolism, we aimed to study whether cross-fostering during the lactation period was sufficient to rescue a programmed obese phenotype in offspring induced by maternal obesity following monosodium L-glutamate (MSG) treatment. Obesity was induced in female Wistar rats by administering subcutaneous MSG (4 mg/g body weight) for the first 5 days of postnatal life. Control and obese female rats were mated in adulthood. The resultant pups were divided into control second generation (F₂) (CTLF₂), MSG-treated second generation (F₂) (MSGF₂), which suckled from their CTL and MSG biological dams, respectively, or CTLF₂-CR, control offspring suckled by MSG dams and MSGF₂-CR, MSG offspring suckled by CTL dams. At 120 days of age, fat tissue accumulation, lipid profile, hypothalamic leptin signalling, glucose tolerance, glucose-induced, and adrenergic inhibition of insulin secretion in isolated pancreatic islets were analysed. Maternal MSG-induced obesity led to an obese phenotype in male offspring, characterized by hyperinsulinaemia, hyperglycaemia, hyperleptinaemia, dyslipidaemia, and impaired leptin signalling, suggesting central leptin resistance, glucose intolerance, impaired glucose-stimulated, and adrenergic inhibition of insulin secretion. Cross-fostering normalized body weight, food intake, leptin signalling, lipid profiles, and insulinaemia, but not glucose homeostasis or insulin secretion from isolated pancreatic islets. Our findings suggest that alterations during the lactation period can mitigate the development of obesity and prevent the programming of adult diseases.

Early redox imbalance is associated with liver dysfunction at weaning in overfed rats

Neonatal overfeeding induced by litter size reduction leads to further obesity and other metabolic disorders, such as liver oxidative stress and microsteatosis at adulthood. We hypothesized that overfeeding causes an early redox imbalance at weaning, which could programme the animals to future liver dysfunction. Thus, we studied lipogenesis, adipogenesis, catecholamine status and oxidative balance in weaned overfed pups. To induce early overfeeding, litters were adjusted to three pups at the 3rd day of lactation (SL group). The control group contained 10 pups per litter until weaning (NL group). Peripheral autonomic nerve function was determined in vivo at 21 days old. Thereafter, pups were killed for further analysis. Differences were considered significant when P < 0.05. The SL pups presented with a higher visceral adipocyte area, higher content of lipogenic enzymes (ACC, FAS) and with a lower content of adipogenic factors (CEBP, PPARγ) in visceral adipose tissue (VAT). Although autonomic nerve activity and adrenal catecholamine production were not significantly altered, catecholamine receptor (β3ADR) content was lower in VAT. The SL pups also presented with higher triglyceride, PPARγ, PPARα and PGC1α contents in liver. In plasma and liver, the SL pups showed an oxidative imbalance, with higher lipid peroxidation and protein oxidation. The SL group presented with a higher serum alanine aminotransferase (ALT). The early increase in lipogenesis in adipose tissue and liver in weaned overfed rats suggests that the higher oxidative stress and lower catecholamine content in VAT are associated with the early development of liver dysfunction and adipocyte hypertrophy.

Calcium reduces vitamin D and glucocorticoid receptors in the visceral fat of obese male rats

Rats overfed during lactation show higher visceral adipose tissue (VAT) mass and metabolic dysfunctions at adulthood. As both vitamin D and glucocorticoids change adipogenesis, parameters related to metabolism and action of these hormones in the adipocyte can be altered in rats raised in small litters (SL). We also studied the antiobesity effects of high calcium diet since it decreases visceral fat in obesity models. On postnatal day (PN) 3, litter size was adjusted to 3pups/dam (SL) to induce overfeeding. Control litters (NL) remained with 10pups/dam until weaning. From PN120 to PN180, half of the SL rats were fed standard chow (SL) and the other half was fed a calcium-supplemented chow (SL-Ca, 10g CaCO3/kg). Both SL groups were heavier and hyperphagic when compared with the NL group; however, SL-Ca rats ate less than SL. SL-Ca rats had decreased VAT mass and adipocyte size, associated with lower hypothalamic NPY content, VAT fat acid synthase content and leptinemia. At PN120, SL rats had increased plasma 25(OH)D3, Cyp27b1 mRNA and glucocorticoid receptor (GR-α) in the VAT, but lower vitamin D receptor (Vdr) mRNA. At PN180, Cyp27b1 and GR-α remained higher, while Vdr normalized in SL rats. SL-Ca rats had normal VAT Cyp27b1 and GR-α, but lower Vdr Thus, higher body mass and glucocorticoid receptors in the VAT of SL rats are normalized by calcium-enriched diet, and Vdr expression in this tissue is reduced, suggesting a possible role of glucocorticoids and vitamin D in calcium action in the adipocyte.

Effect of Early Overfeeding on Palatable Food Preference and Brain Dopaminergic Reward System at Adulthood: Role of Calcium Supplementation

Rats raised in small litters (SL) are obese and hyperphagic. In the present study, we evaluated whether obesity is associated with changes in the mesocorticolimbic dopaminergic reward system in these animals at adulthood. We also assessed the anti-obesity effects of dietary calcium supplementation. To induce early overfeeding, litters were adjusted to three pups on postnatal day (PN)3 (SL group). Control litters were kept with 10 pups each until weaning (NL group). On PN120, SL animals were subdivided into two groups: SL (standard diet) and SL-Ca [SL with calcium supplementation (10 g calcium carbonate/kg rat chow) for 60 days]. On PN175, animals were subjected to a food challenge: animals could choose between a high-fat (HFD) or a high-sugar diet (HSD). Food intake was recorded after 30 min and 12 h. Euthanasia occurred on PN180. SL rats had higher food intake, body mass and central adiposity. Sixty days of dietary calcium supplementation (SL-Ca) prevented these changes. Only SL animals preferred the HFD at 12 h. Both SL groups had lower tyrosine hydroxylase content in the ventral tegmental area, lower dopaminergic transporter content in the nucleus accumbens, and higher type 2 dopamine receptor (D2R) content in the hypothalamic arcuate nucleus (ARC). They also had higher neuropeptide Y (NPY) and lower pro-opiomelanocortin contents in the ARC. Calcium treatment normalised only D2R and NPY contents. Precocious obesity induces long-term effects in the brain dopaminergic system, which can be associated with an increased preference for fat at adulthood. Calcium treatment prevents this last alteration, partially through its actions on ARC D2R and NPY proteins.

Protein Restriction During the Last Third of Pregnancy Malprograms the Neuroendocrine Axes to Induce Metabolic Syndrome in Adult Male Rat Offspring

Metabolic malprogramming has been associated with low birth weight; however, the interplay between insulin secretion disruption and adrenal function upon lipid metabolism is unclear in adult offspring from protein-malnourished mothers during the last third of gestation. Thus, we aimed to study the effects of a maternal low-protein diet during the last third of pregnancy on adult offspring metabolism, including pancreatic islet function and morphophysiological aspects of the liver, adrenal gland, white adipose tissue, and pancreas. Virgin female Wistar rats (age 70 d) were mated and fed a protein-restricted diet (4%, intrauterine protein restricted [IUPR]) from day 14 of pregnancy until delivery, whereas control dams were fed a 20.5% protein diet. At age 91 d, their body composition, glucose-insulin homeostasis, ACTH, corticosterone, leptin, adiponectin, lipid profile, pancreatic islet function and liver, adrenal gland, and pancreas morphology were assessed. The birth weights of the IUPR rats were 20% lower than the control rats (P < .001). Adult IUPR rats were heavier, hyperphagic, hyperglycemic, hyperinsulinemic, hyperleptinemic, and hypercorticosteronemic (P < .05) with higher low-density lipoprotein cholesterol and lower high-density lipoprotein cholesterol, adiponectin, ACTH, and insulin sensitivity index levels (P < .01). The insulinotropic action of glucose and acetylcholine as well as muscarinic and adrenergic receptor function were impaired in the IUPR rats (P < .05). Maternal undernutrition during the last third of gestation disrupts the pancreatic islet insulinotropic response and induces obesity-associated complications. Such alterations lead to a high risk of metabolic syndrome, characterized by insulin resistance, visceral obesity, and lower high-density lipoprotein cholesterol.

Euterpe oleracea Mart.-Derived Polyphenols Protect Mice from Diet-Induced Obesity and Fatty Liver by Regulating Hepatic Lipogenesis and Cholesterol Excretion

The aim of this study was to investigate the effect of a polyphenol-rich Açaí seed extract (ASE, 300 mg/kg-1d-1) on adiposity and hepatic steatosis in mice that were fed a high-fat (HF) diet and its underlying mechanisms based on hepatic lipid metabolism and oxidative stress. Four groups were studied: C57BL/6 mice that were fed with standard diet (10% fat, Control), 10% fat + ASE (ASE), 60% fat (HF), and 60% fat + ASE (HF + ASE) for 12 weeks. We evaluated the food intake, body weight gain, serum glucose and lipid profile, hepatic cholesterol and triacyglycerol (TG), hepatic expression of pAMPK, lipogenic proteins (SREBP-1c, pACC, ACC, HMG-CoA reductase) and cholesterol excretion transporters, ABCG5 and ABCG8. We also evaluated the steatosis in liver sections and oxidative stress. ASE reduced body weight gain, food intake, glucose levels, accumulation of cholesterol and TG in the liver, which was associated with a reduction of hepatic steatosis. The increased expressions of SREBP-1c and HMG-CoA reductase and reduced expressions of pAMPK and pACC/ACC in HF group were antagonized by ASE. The ABCG5 and ABCG8 transporters expressions were increased by the extract. The antioxidant effect of ASE was demonstrated in liver of HF mice by restoration of SOD, CAT and GPx activities and reduction of the increased levels of malondialdehyde and protein carbonylation. In conclusion, ASE substantially reduced the obesity and hepatic steatosis induced by HF diet by reducing lipogenesis, increasing cholesterol excretion and improving oxidative stress in the liver, providing a nutritional resource for prevention of obesity-related adiposity and hepatic steatosis.

Neonatal Nicotine Exposure Leads to Hypothalamic Gliosis in Adult Overweight Rats

Astrocytes and microglia, the immune competent cells of central nercous system, can be activated in response to metabolic signals such as obesity and hyperleptinaemia. In rats, maternal exposure to nicotine during lactation leads to central obesity, hyperleptinaemia, leptin resistance and alterations in hypothalamic neuropeptides in the offspring during adulthood. In the present study, we studied the activation of astrocytes and microglia, as well as the pattern of inflammatory mediators, in adult offspring of this experimental model. On postnatal day 2 (P2), osmotic minipumps releasing nicotine (NIC) (-6 mg/kg/day) or saline for 14 days were s.c. implanted in dams. Male offspring were killed on P180 and hypothalamic immunohistochemistry, retroperitoneal white adipose tissue (WAT) polymerase chain reaction analysis and multiplex analysis for plasma inflammatory mediators were carried out. At P180, NIC astrocyte cell number was higher in the arcuate nucleus (ARC) (medial: +82%; lateral: +110%), in the paraventricular nucleus (PVN) (+144%) and in the lateral hypothalamus (+121%). NIC glial fibrillary acidic protein fibre density was higher in the lateral ARC (+178%) and in the PVN (+183%). Interleukin-6 was not affected in the hypothalamus. NIC monocyte chemotactic protein 1 was only higher in the periventricular nucleus (+287%). NIC microglia (iba-1-positive) cell number was higher (+68%) only in the PVN, as was the chemokine (C-X3-C motif) receptor 1 density (+93%). NIC interleukin-10 was lower in the WAT (-58%) and plasma (-50%). Thus, offspring of mothers exposed to nicotine during lactation present hypothalamic astrogliosis at adulthood and microgliosis in the PVN.

Protein-energy malnutrition at mid-adulthood does not imprint long-term metabolic consequences in male rats

PURPOSE

The long-term effects of the development of chronic metabolic diseases such as type 2 diabetes and obesity have been associated with nutritional insults in critical life stages. In this study, we evaluated the effect of a low-protein diet on metabolism in mid-adulthood male rats.

METHODS

At 90 days of age, Wistar male rats were fed a low-protein diet (4.0 %, LP group) for 30 days, whereas control rats were fed a normal-protein diet (20.5 %, NP group) throughout their lifetimes. To allow for dietary rehabilitation, from 120 to 180 days of age, the LP rats were fed a normal-protein diet. Then, we measured body composition, fat stores, glucose-insulin homeostasis and pancreatic islet function.

RESULTS

At 120 days of age, just after low-protein diet treatment, the LP rats displayed a strong lean phenotype, hypoinsulinemia, as assessed under fasting and glucose tolerance test conditions, as well as weak pancreatic islet insulinotropic response to glucose and acetylcholine (p < 0.01). At 180 days of age, after poor-protein diet rehabilitation, the LP rats displayed a slight lean phenotype (p < 0.05), which was associated with a high body weight gain (p < 0.001). Additionally, fat pad accumulation, glycemia and insulinemia, as well as the pancreatic islet insulinotropic response, were not significantly different between the LP and NP rats (p > 0.05).

CONCLUSIONS

Taken together, the present data suggest that the effects of dietary restriction as a stressor in adulthood are reversible with dietary rehabilitation, indicating that adulthood is not a sensitive or critical time window for metabolic programming.

Maternal prolactin inhibition causes changes in leptin at 22- and 30-day-old pups

Breastfeeding is associated with obesity prevention. We showed previously that prolactin inhibition at the end of lactation causes hyperleptinemia at weaning (PN21) and programs for obesity, insulin resistance, dyslipidemia, and leptin resistance (PN180). Here, we evaluate the source of neonatal hyperleptinemia and how it develops during the nutritional transition from milk through solid food. Lactating rats were treated with bromocriptine (BRO), a prolactin inhibitor, 0.5 mg twice a day, or saline (CON) for the last 3 days of lactation. All parameters were studied at PN22 and PN30. At PN22, BRO-treated rats showed lower food intake, body mass, and body length. At PN30, only body length and mesenteric fat mass were lower. Despite normal plasma leptin levels at PN22, the adipose tissue leptin mRNA expression was lower, while plasma leptin was higher in PN30, possibly due to a higher adipose mesenteric tissue production. At PN22, the hypothalamus seems to be more sensitive to leptin, since OBR and STAT3 are higher. Conversely, at PN30 leptin signaling pathway is suggestive of leptin resistance with lower STAT3 and higher SOCS3 in hypothalamus and consequently higher NPY. Glycemia was lower at PN22 and higher at PN30, without changes in plasma insulin levels. At PN30, BRO-treated rats had other metabolic changes such as higher plasma cholesterol, lower HDL-c, higher hepatic cholesterol and AST, suggesting a liver dysfunction. Our data show that milk supply can exert a crucial role in the imprinting of a second leptin peak, which is important for survival adaptation to adverse nutritional conditions.

Resveratrol treatment rescues hyperleptinemia and improves hypothalamic leptin signaling programmed by maternal high-fat diet in rats

PURPOSE

Perinatal high-fat diet is associated with obesity and metabolic diseases in adult offspring. Resveratrol has been shown to exert antioxidant and anti-obesity actions. However, the effects of resveratrol on leptinemia and leptin signaling are still unknown as well as whether resveratrol treatment can improve metabolic outcomes programmed by maternal high-fat diet. We hypothesize that resveratrol treatment in male rats programmed by high-fat diet would decrease body weight and food intake, and leptinemia with changes in central leptin signaling.

METHODS

Female Wistar rats were divided into two groups: control group (C), which received a standard diet containing 9 % of the calories as fat, and high-fat group (HF), which received a diet containing 28 % of the calories as fat. Dams were fed in C or HF diet during 8 weeks before mating and throughout gestation and lactation. C and HF male offspring received standard diet throughout life. From 150 until 180 days of age, offspring received resveratrol (30 mg/Kg body weight/day) or vehicle (carboxymethylcellulose).

RESULTS

HF offspring had increased body weight, hyperphagia and increased subcutaneous and visceral fat mass compared to controls, and resveratrol treatment decreased adiposity. HF offspring had increased leptinemia as well as increased SOCS3 in the arcuate nucleus of the hypothalamus, which suggest central leptin resistance. Resveratrol treatment rescued leptinemia and increased p-STAT3 content in the hypothalamus with no changes in SOCS3, suggesting improvement in leptin signaling.

CONCLUSIONS

Collectively, our data suggest that resveratrol could reverse hyperleptinemia and improve central leptin action in adult offspring from HF mothers attenuating obesity.

Effects of maternal nicotine exposure on thyroid hormone metabolism and function in adult rat progeny

Postnatal nicotine exposure leads to obesity and hypothyroidism in adulthood. We studied the effects of maternal nicotine exposure during lactation on thyroid hormone (TH) metabolism and function in adult offspring. Lactating rats received implants of osmotic minipumps releasing nicotine (NIC, 6 mg/kg per day s.c.) or saline (control) from postnatal days 2 to 16. Offspring were killed at 180 days. We measured types 1 and 2 deiodinase activity and mRNA, mitochondrial α-glycerol-3-phosphate dehydrogenase (mGPD) activity, TH receptor (TR), uncoupling protein 1 (UCP1), hypothalamic TRH, pituitary TSH, and in vitro TRH-stimulated TSH secretion. Expression of deiodinase mRNAs followed the same profile as that of the enzymatic activity. NIC exposure caused lower 5'-D1 and mGPD activities; lower TRβ1 content in liver as well as lower 5'-D1 activity in muscle; and higher 5'-D2 activity in brown adipose tissue (BAT), heart, and testis, which are in accordance with hypothyroidism. Although deiodinase activities were not changed in the hypothalamus, pituitary, and thyroid of NIC offspring, UCP1 expression was lower in BAT. Levels of both TRH and TSH were lower in offspring exposed to NIC, which presented higher basal in vitro TSH secretion, which was not increased in response to TRH. Thus, the hypothyroidism in NIC offspring at adulthood was caused, in part, by in vivo TRH-TSH suppression and lower sensitivity to TRH. Despite the hypothyroid status of peripheral tissues, these animals seem to develop an adaptive mechanism to preserve thyroxine to triiodothyronine conversion in central tissues.

Butter naturally enriched in cis-9, trans-11 CLA prevents hyperinsulinemia and increases both serum HDL cholesterol and triacylglycerol levels in rats

BACKGROUND

Evidence from in vitro and animal studies indicates that conjugated linoleic acid (CLA) possesses anti-diabetic properties, which appear to be attributed to cis-9, trans-11 CLA, the major CLA isomer in ruminant fat. However, there is a shortage of studies addressing CLA from natural source. The present study aimed to evaluate the effects of butter naturally enriched in cis-9, trans-11 CLA on parameters related to glucose tolerance, insulin sensitivity and dyslipidemia in rats.

METHODS

Forty male Wistar rats were randomly assigned to the following dietary treatments (n=10/group), for 60 days: 1) Normal fat-Soybean oil (NF-So): diet containing 4.0% soybean oil (SO); 2) High Fat-Control Butter (HF-Cb): diet containing 21.7% control butter and 2.3% SO; 3) High Fat-CLA enriched Butter (HF-CLAb): diet containing 21.7% cis-9, trans-11 CLA-enriched butter and 2.3% SO; and 4) High fat-Soybean oil (HF-So): diet containing 24.0% SO. HF-Cb and HF-CLAb diets contained 0.075% and 0.235% of cis-9, trans-11 CLA, respectively.

RESULTS

HF-CLAb-fed rats had lower serum insulin levels at fasting than those fed with the HF-Cb diet, while the PPARγ protein levels in adipose tissue was increased in HF-CLAb-fed rats compared to HF-Cb-fed rats. Furthermore, R-QUICK was lower in HF-Cb than in NF-So group, while no differences in R-QUICK were observed among NF-So, HF-CLAb and HF-So groups. Serum HDL cholesterol levels were higher in HF-CLAb-fed rats than in those fed NF-So, HF-Cb and HF-So diets, as well as higher in NF-So-fed rats than in HF-Cb and HF-So-fed rats. HF-CLAb, HF-Cb and HF-So diets reduced serum LDL cholesterol levels when compared to NF-So, whereas serum triacylglycerol levels were increased in HF-CLAb.

CONCLUSION

Feeding rats on a high-fat diet containing butter naturally enriched in cis-9, trans-11 CLA prevented hyperinsulinemia and increased HDL cholesterol, which could be associated with higher levels of cis-9, trans-11 CLA, vaccenic acid, oleic acid and lower levels of short and medium-chain saturated fatty acids from butter naturally modified compared to control butter. On the other hand CLA-enriched butter also increased serum triacylglycerol levels, which could be associated with concomitant increases in the content of trans-9 and trans-10 C18:1 isomers in the CLA-enriched butter.

Resveratrol prevents hyperleptinemia and central leptin resistance in adult rats programmed by early weaning

We have previously shown that early weaning in rats increases the risk of obesity and insulin resistance at adulthood, and leptin resistance can be a prime factor leading to these changes. Resveratrol is reported to decrease oxidative stress, insulin resistance, and cardiovascular risk. However, there is no report about its effect on leptin resistance. Thus, in this study we have evaluated resveratrol-preventing effect on the development of visceral obesity, insulin, and leptin resistance in rats programmed by early weaning. To induce early weaning, lactating dams were separated into 2 groups: early weaning (EW)--dams were wrapped with a bandage to interrupt lactation in the last 3 days of lactation and control (C)--dams whose pups had free access to milk during throughout lactation period (21 days). At 150 days-old, EW offspring were subdivided into 2 groups: EW+res--treated with resveratrol solution (30 mg/kg BW/day) or EW--receiving equal volume of vehicle solution, both given by gavage during 30 days. Control group received vehicle solution. Resveratrol prevented the higher body weight, hyperphagia, visceral obesity, hyperleptinemia, hyperglycemia, insulin resistance, and hypoadiponectinemia at adulthood in animals that were early weaned. Leptin resistance, associated with lower JAK2 and pSTAT3 and higher NPY in hypothalamus of EW rats were also normalized by resveratrol. The present results suggest that resveratrol is useful as therapeutic tool in treating obesity, mainly because it prevents the development of central leptin resistance.

Bone structure and strength are enhanced in rats programmed by early overfeeding

Childhood obesity is growing in prevalence. Obesity and bone dysfunctions may be related disorders, and therefore our aim was to study the impact of the early overfeeding (EO) in offspring bone health since weaning up to adulthood. To induce EO during lactation, litter size was adjusted to 3 male rats per litter (SL). Litter containing 10 pups per mother was the control (NL). Bone tissue was evaluated by dual-energy X-ray absorptiometry, computed tomography, microcomputed tomography, biomechanical tests, and serum analyses. SL offspring presented higher body weight, fat mass, lean mass from 21 up to 180 days, hyperphagia, and higher visceral fat mass. Bone analysis showed that SL offspring presented higher total bone mineral density (BMD) only at 180 days, and higher total bone mineral content and higher bone area from 21 until 180 days. At 180 days, SL offspring presented higher femur BMD and fourth lumbar vertebra (LV4) BMD, higher femoral head radiodensity and LV4 vertebral body radiodensity, lower trabecular pattern factor and trabecular separation, however with higher trabecular number, higher maximal load, resilience, stiffness and break load, and lower break deformation. SL group had, at 180 days, higher osteocalcin and lower C-terminal cross-linked telopeptide of type I collagen (CTX I). We have shown that the excess of fat mass contributed to an increased bone mass, and hypothesized that this increase could be mediated by the hypothyroidism and previous higher thyroid hormone action and hyperleptinemia at weaning. Furthermore, the increased biomechanical loading due to increased body weight probably help us to understand the protective effects obesity exerts upon bone health.

Bone metabolism in obese rats programmed by early weaning

OBJECTIVE

Obesity and osteoporosis seem to have a common pathogenesis, especially because bone and adipose tissue have common origins. Since early weaning (EW) decreases adipogenesis and osteogenesis in neonate, further programming for obesity and hyperleptinemia, we hypothesized that these changes in adipogenesis could affect bone metabolism.

MATERIALS/METHODS

Lactating rats were separated into 3 groups: control - dams whose pups ate milk throughout lactation; mechanical EW (MEW) - dams were involved with a bandage interrupting suckling in the last 3days of lactation; pharmacological EW (PEW) - dams were bromocriptine-treated (0.5mg/twice a day via intraperitoneal injection) 3days before weaning. The adult offspring was subjected to dual-energy X-ray absorptiometry and bone tissue was also evaluated by computed tomography, microcomputed tomography and biomechanical tests, beyond serum analyses.

RESULTS

MEW and PEW presented higher total bone mineral density (BMD), total bone mineral content, spine BMD and bone area in postnatal day 150 (PN150). In PN180, both groups also presented increase of these parameters and higher femur BMD and fourth lumbar vertebra (LV4) BMD, femoral head radiodensity and LV4 vertebral body radiodensity, trabecular number, stiffness and break load; lower trabecular separation, maximal deformation and break deformation, and also hyperleptinemia and higher visceral fat mass and 25-hydroxivitamin D, whereas parathyroid hormone was unchanged. Serum C-terminal cross-linked telopeptide of type I collagen was lower for both groups.

CONCLUSIONS

Since both models program for obesity and increased bone mass, and leptin increases plasma vitamin D levels, probably leptin is the link between obesity and higher bone mass.

Effects of running wheel training on adult obese rats programmed by maternal prolactin inhibition

The inhibition of maternal prolactin production in late lactation leads to metabolic syndrome and hypothyroidism in adult offspring. Physical training is a therapeutic strategy that could prevent or reverse this condition. We evaluated the effects of a short-duration low-intensity running wheel training program on the metabolic and hormonal alterations in rats. Lactating Wistar rats were treated with bromocriptine (Bro, 1 mg twice a day) or saline on days 19, 20, and 21 of lactation, and the training of offspring began at 35 days of age. Offspring were divided into sedentary and trained controls (C-Sed and C-Ex) and sedentary and trained Bro-treated rats (Bro-Sed and Bro-Ex). Chronic exercise delayed the onset of weight gain in Bro-Ex offspring, and the food intake did not change during the experimental period. At 180 days, visceral fat mass was higher (+46%) in the Bro-Sed offspring than in C-Sed and Bro-Ex rats. As expected, running capacity was higher in trained animals. Most parameters observed in the Bro-Sed offspring were consistent with hypothyroidism and metabolic syndrome and were reversed in the Bro-Ex group. Chronic exercise did not influence the muscle glycogen in the C-Ex group; however, liver glycogen was higher (+30%) in C-Ex group and was unchanged in both Bro offspring groups. Bro-Ex animals had higher plasma lactate dehydrogenase levels, indicating skeletal muscle damage and intolerance of the training program. Low-intensity chronic training is able to normalize many clinical aspects in Bro animals; however, these animals might have had a lower threshold for exercise adaptation than the control rats.

Endocrine effects of tobacco smoke exposure during lactation in weaned and adult male offspring

Children from pregnant smokers show more susceptibility to develop obesity in adult life. Previously, we failed to demonstrate a program for obesity in rat offspring only when the mothers were exposed to tobacco smoke during lactation. Here, we studied the short- and long-term effects of smoke exposure (SE) to both dams and their pups during lactation on endocrine and metabolic parameters. For this, we designed an experimental model where nursing rats and their pups were divided into two groups: SE group, exposed to smoke in a cigarette smoking machine (four times/day, from the third to the 21st day of lactation), and group, exposed to filtered air. Pups were killed at 21 and 180 days. At weaning, SE pups showed lower body weight (7%), length (5%), retroperitoneal fat mass (59%), visceral adipocyte area (60%), and higher subcutaneous adipocyte area (95%) with hypoinsulinemia (-29%), hyperthyroxinemia (59%), hypercorticosteronemia (60%), and higher adrenal catecholamine content (+58%). In adulthood, SE offspring showed higher food intake (+10%), body total fat mass (+50%), visceral fat mass (retroperitoneal: 55%; mesenteric: 67%; and epididymal: 55%), and lower subcutaneous adipocyte area (24%) with higher serum glucose (11%), leptin (85%), adiponectin (1.4-fold increase), total triiodothyronine (71%), free thyroxine (57%), TSH (36%), triglycerides (65%), VLDL cholesterol (+66%), and HDL cholesterol (91%) levels and lower corticosteronemia (41%) and adrenal catecholamine content (57%). Our present findings suggest that tobacco SE to both dams and their pups during lactation causes malnutrition in early life that programs for obesity and hormonal and metabolic disturbances in adulthood, only if the pups are submitted to the same smoke environment as the mother.

Two models of early weaning decreases bone structure by different changes in hormonal regulation of bone metabolism in neonate rat

During the last decade a great concern has developed for determining what factors influence bone mineral accretion in healthy children. Mother's milk represents the primary source of calcium and other nutrients in the neonate. The development of bone and adipose tissue has common origins. Since early weaning decreases adipogenesis in neonate, our aim was to evaluate bone metabolism in 2 models of early weaning (EW) in neonate rats. Lactating rats were separated into 3 groups: control: pups had free access to milk; MEW: dams were involved with a bandage mechanically (M) interrupting lactation in the last 3 days; and PEW: dams were pharmacologically (P) treated to block prolactin (0.5 mg bromocryptine/twice a day) 3 days before standard weaning. Significant difference had p<0.05. At weaning, MEW and PEW pups presented lower body weight (-18% and -15%), total body fat (-26% and -27%), total bone mineral density (-7% and -6%), total bone mineral content (-30% and -32%), bone area (-28% and -30%), serum osteocalcin (-20% and -55%), and higher C-terminal cross-linked telopeptide of type I collagen (CTX-I) (1.3 and 1.1-fold increase). However, serum ionized calcium was lower only in MEW pups (-34%), 25-hydroxyvitamin D was higher (1.4-fold increase), and PTH was lower (-26%) only in PEW group. The present study shows that both early weaning models leads to an impairment of osteogenesis associated with lower adipogenesis by different mechanisms, involving mainly changes in vitamin D and PTH.

Poor pubertal protein nutrition disturbs glucose-induced insulin secretion process in pancreatic islets and programs rats in adulthood to increase fat accumulation

Similar to gestation/lactation, puberty is also a critical phase in which neuronal connections are still being produced and during which metabolic changes may occur if nutrition is disturbed. In the present study we aimed to determine whether peripubertal protein restriction induces metabolic programming. Thirty-day-old male rats were fed either a low protein (LP group) diet (4% w/w protein) or a normal protein (NP group) diet (23%) until 60 days of age, when they received the NP diet until they were 120 days old. Body weight (BW), food intake, fat tissue accumulation, glucose tolerance, and insulin secretion were evaluated. The nerve electrical activity was recorded to evaluate autonomous nervous system (ANS) function. Adolescent LP rats presented hypophagia and lower BW gain during the LP diet treatment (P<0.001). However, the food intake and BW gain by the LP rats were increased (P<0.001) after the NP diet was resumed. The LP rats presented mild hyperglycemia, hyperinsulinemia, severe hyperleptinemia upon fasting, peripheral insulin resistance and increased fat tissue accumulation and vagus nerve activity (P<0.05). Glucose-induced insulin secretion was greater in the LP islets than in the NP islets; however, the cholinergic response was decreased (P<0.05). Compared with the islets from the NP rats, the LP islets showed changes in the activity of muscarinic receptors (P<0.05); in addition, the inhibition of glucose-induced insulin secretion by epinephrine was attenuated (P<0.001). Protein restriction during adolescence caused high-fat tissue accumulation in adult rats. Islet dysfunction could be related to an ANS imbalance.

Developmental plasticity of endocrine disorders in obesity model primed by early weaning in dams

Early weaning is associated with changes in the developmental plasticity. Here, we studied the adipocytes morphology, adipokines expression or content in adipose tissue as well as adrenal and thyroid function of neonate and adult offspring primed by early weaning. After birth, lactating rats were divided into 2 groups: EW (early weaning)--dams were wrapped with a bandage to block access to milk during the last 3 days of lactation, and Control--dams whose pups had free access to milk throughout lactation (21 days). At postnatal day (PN) 21, EW pups had lower visceral and subcutaneous adipocyte area (-67.7% and -62%, respectively), body fat mass (-26%), and leptin expression in visceral adipocyte (-64%) but higher leptin expression in subcutaneous adipocyte (2.9-fold increase). Adrenal evaluations were normal, but neonate EW pups presented lower serum T3 (-55%) and TSH (-44%). At PN 180, EW offspring showed higher food intake, higher body fat mass (+21.6%), visceral and subcutaneous adipocyte area (both 3-fold increase), higher leptin (+95%) and ADRβ3 (2-fold increase) content in visceral adipose tissue, and higher adiponectin expression in subcutaneous adipose tissue (+47%) but lower in visceral adipose tissue (-40%). Adult EW offspring presented higher adrenal catecholamine content (+31%), but no changes in serum corticosterone or thyroid status. Thus, early weaning primed for hypothyroidism at weaning, which can be associated with the adipocyte hypertrophy at adulthood. The marked changes in catecholamine adrenal content and visceral adipocyte ADRB3 are generally found in obesity, contributing to the development of other cardiovascular and metabolic disturbances.

Effects of a moderate physical training on the leptin synthesis by adipose tissue of adult rats submitted to a perinatal low-protein diet

The aim of the study was to verify if moderate physical training affects leptin content in visceral and subcutaneous adipose tissue of adult rats subjected to a low-protein diet during the perinatal period. Male Wistar rats were divided into 2 groups according to their mother's diet during gestation and lactation: control (17% casein, C, n=12) and low-protein (8% casein, LP, n=12). On postnatal day 60, half of each group was submitted to moderate physical training (8 wks, 5 d · wk - 1, 60 min · d - 1, at 70% of VO2max, T) or not. After the physical training period, visceral and subcutaneous adipose tissues were removed. Leptin content was evaluated by western blotting. Starting from the fifth week on, T pups showed a reduction in the body weight. Similarly, LP+T offspring showed a lower body weight starting from the sixth week on. Western blotting analysis showed that leptin content in the visceral tissue was higher in the LP rats (p<0.01) and it was reversed in LP+T. No difference was found in the subcutaneous tissue. Moderate physical training attenuated the effects of a perinatal low-protein diet on the leptin content in visceral adipose tissue in adult offspring.

Maternal high-fat diet induces obesity and adrenal and thyroid dysfunction in male rat offspring at weaning

Maternal nutritional status affects the future development of offspring. Both undernutrition and overnutrition in critical periods of life (gestation or lactation) may cause several hormonal changes in the pups and programme obesity in the adult offspring. We have shown that hyperleptinaemia during lactation results in central leptin resistance, higher adrenal catecholamine secretion, hyperthyroidism, and higher blood pressure and heart rate in the adult rats. Here, we evaluated the effect of a maternal isocaloric high-fat diet on breast milk composition and its impact on leptinaemia, energy metabolism, and adrenal and thyroid function of the offspring at weaning. We hypothesised that the altered source of fat in the maternal diet even under normal calorie intake would disturb the metabolism of the offspring. Female Wistar rats were fed a normal (9% fat; C group) or high-fat diet (29% fat as lard; HF group) for 8 weeks before mating and during pregnancy and lactation. HF mothers presented increased total body fat content after 8 weeks (+27%, P < 0.05) and a similar fat content at the end of lactation. In consequence, the breast milk from the HF group had higher concentration of protein (+18%, P < 0.05), cholesterol (+52%, P < 0.05) and triglycerides (+86%, P < 0.05). At weaning, HF offspring had increased body weight (+53%, P < 0.05) and adiposity (2 fold, P < 0.05), which was associated with lower β3-adrenoreceptor content in adipose tissue (-40%, P < 0.05). The offspring also presented hyperglycaemia (+30%, P < 0.05) and hyperleptinaemia (+62%, P < 0.05). In the leptin signalling pathway in the hypothalamus, we found lower p-STAT3/STAT3 (-40%, P < 0.05) and SOCS3 (-55%, P < 0.05) content in the arcuate nucleus, suggesting leptin resistance. HF offspring also had higher adrenal catecholamine content (+17%, P < 0.05), liver glycogen content (+50%, P < 0.05) and hyperactivity of the thyroid axis at weaning. Our results suggest that a high fat diet increases maternal body fat and this additional energy is transferred to the offspring during lactation, since at weaning the dams had normal fat and the pups were obese. The higher fat and protein concentrations in the breast milk seemed to induce early overnutrition in the HF offspring. In addition to storing energy as fat, the HF offspring had a larger reserve of glycogen and hyperglycaemia that may have resulted from increased gluconeogenesis. Hyperleptinaemia may stimulate both adrenal medullary and thyroid function, which may contribute to the development of cardiovascular diseases. These early changes induced by the maternal high-fat diet may contribute to development of metabolic syndrome.