Cranberry (Vaccinium macrocarpon) extract treatment improves triglyceridemia, liver cholesterol, liver steatosis, oxidative damage and corticosteronemia in rats rendered obese by high fat diet.

PURPOSE: Obese individuals have higher production of reactive oxygen species, which leads to oxidative damage. We hypothesize that cranberry extract (CE) can improve this dysfunction in HFD-induced obesity in rats since it has an important antioxidant activity. Here, we evaluated the effects of CE in food intake, adiposity, biochemical and hormonal parameters, lipogenic and adipogenic factors, hepatic morphology and oxidative balance in a HFD model. METHODS: At postnatal day 120 (PN120), male Wistar rats were assigned into two groups: (1) SD (n = 36) fed with a standard diet and (2) HFD (n = 36), fed with a diet containing 44.5% (35.2% from lard) energy from fat. At PN150, 12 animals from SD and HFD groups were killed while the others were subdivided into four groups (n = 12/group): animals that received 200 mg/kg cranberry extract (SD CE, HFD CE) gavage/daily/30 days or water (SD, HFD). At PN180, animals were killed. RESULTS: HFD group showed higher body mass and visceral fat, hypercorticosteronemia, higher liver glucocorticoid sensitivity, cholesterol and triglyceride contents and microsteatosis. Also, HFD group had higher lipid peroxidation (plasma and tissues) and higher protein carbonylation (liver and adipose tissue) compared to SD group. HFD CE group showed lower body mass gain, hypotrygliceridemia, hypocorticosteronemia, and lower hepatic cholesterol and fatty acid synthase contents. HFD CE group displayed lower lipid peroxidation, protein carbonylation (liver and adipose tissue) and accumulation of liver fat compared to HFD group. CONCLUSION: Although adiposity was not completely reversed, cranberry extract improved the metabolic profile and reduced oxidative damage and steatosis in HFD-fed rats, which suggests that it can help manage obesity-related disorders.

Effects of postnatal bromocriptine injection on thyroid function and prolactinemia of rats at adulthood.

Previously, we demonstrated that maternal prolactin inhibition at the end of lactation, using bromocriptine (BRO), leads to an increase in leptin transfer via milk and induces the adult progeny to present hypothyroidism, leptin resistance and metabolic syndrome (obesity, hyperglycemia, hypertriglyceridemia, lower HDL). To test if these alterations are due to direct BRO action on the pups, in the present study we evaluated the long-term effects of direct injection of BRO (0.1µg/once daily) in male Wistar rats from postnatal (PN) day 1 to 10 (early treatment) or from PN11 to 20 (late treatment) on: food intake, body mass, cardiovascular parameters, hormone profile, hypothalamic leptin signaling, glucose homeostasis and thyroid hormone-dependent proteins. The respective controls were injected with methanol-saline. Offspring were killed at adulthood (PN180). Adult PN1-10 BRO-treated animals had lower food intake, hypoprolactinemia, lower leptin action (lower OBR-b, STAT-3 and SOCS-3 mRNA levels in the arcuate nucleus), lower TRH-TSH-thyroid axis as well as lower thyroid hormone markers. On the other hand, adult animals that were BRO-treated during the PN11-20 period showed hyperphagia, higher blood pressure, higher prolactinemia and OBR-b, higher TRH and plasma T3, hypercorticosteronemia as well as higher Dio2 and UCP1 mRNA expression in the brown adipose tissue. Glucose homeostasis was not changed treatment in either period. Our data show that early and late dopamine overexposure during lactation induces diverse metabolic disturbances later in life, increasing the risk of thyroid dysfunction and, consequently, changes in prolactinemia.

Astrocytes Assemble Thalamocortical Synapses by Bridging NRX1α and NL1 via Hevin.

Proper establishment of synapses is critical for constructing functional circuits. Interactions between presynaptic neurexins and postsynaptic neuroligins coordinate the formation of synaptic adhesions. An isoform code determines the direct interactions of neurexins and neuroligins across the synapse. However, whether extracellular linker proteins can expand such a code is unknown. Using a combination of in vitro and in vivo approaches, we found that hevin, an astrocyte-secreted synaptogenic protein, assembles glutamatergic synapses by bridging neurexin-1alpha and neuroligin-1B, two isoforms that do not interact with each other. Bridging of neurexin-1alpha and neuroligin-1B via hevin is critical for the formation and plasticity of thalamocortical connections in the developing visual cortex. These results show that astrocytes promote the formation of synapses by modulating neurexin/neuroligin adhesions through hevin secretion. Our findings also provide an important mechanistic insight into how mutations in these genes may lead to circuit dysfunction in diseases such as autism.

Early weaning by maternal prolactin inhibition leads to higher neuropeptide Y and astrogliosis in the hypothalamus of the adult rat offspring.

The suppression of prolactin production with bromocriptine (BRO) in the last 3 d of lactation reduces milk yield (early weaning) and increases the transfer of leptin through the milk, causing hyperleptinaemia in pups. In adulthood, several changes occur in the offspring as a result of metabolic programming, including overweight, higher visceral fat mass, hypothyroidism, hyperglycaemia, insulin resistance, hyperleptinaemia and central leptin resistance. In the present study, we investigated whether overweight rats programmed by early weaning with maternal BRO treatment have hypothalamic alterations in adulthood. We analysed the expression of neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART), pro-opiomelanocortin (POMC) and α-melanocyte-stimulating hormone (α-MSH) by immunohistochemistry in the following hypothalamic nuclei: medial and lateral arcuate nucleus (ARC); paraventricular nucleus (PVN); lateral hypothalamus (LH). Additionally, we sought to determine whether these programmed rats exhibited hypothalamic inflammation as indicated by astrogliosis. NPY immunostaining showed a denser NPY-positive fibre network in the ARC and PVN (+82% in both nuclei) of BRO offspring. Regarding the anorexigenic neuropeptides, no difference was found for CART, POMC and α-MSH. The number of astrocytes was higher in all the nuclei of BRO rats. The fibre density of glial fibrillary acidic protein was also increased in both medial and lateral ARC (6·06-fold increase and 9·13-fold increase, respectively), PVN (5·75-fold increase) and LH (2·68-fold increase) of BRO rats. We suggest that early weaning has a long-term effect on the expression of NPY as a consequence of developmental plasticity, and the presence of astrogliosis indicates hypothalamic inflammation that is closely related to overweight and hyperleptinaemia observed in our model.

Maternal nicotine exposure during lactation alters hypothalamic neuropeptides expression in the adult rat progeny.

Maternal exposure to nicotine during lactation causes hyperleptinemia in the pups and, at adulthood, these animals are overweight and hyperleptinemic, while, in their hypothalamus, the leptin signaling pathway is reduced, evidencing a central leptin resistance. Then, we evaluated the expression of pro-opiomelanocortin (POMC), alpha-melanocyte stimulating hormone (α-MSH), cocaine and amphetamine-regulated transcript (CART), neuropeptide Y (NPY), agouti-related peptide (AgRP) and others in different hypothalamic nuclei in order to better understand the mechanisms underlying the obese phenotype observed in these animals at adulthood. On the 2nd postnatal day (P2), dams were subcutaneously implanted with osmotic minipumps releasing nicotine (NIC-6 mg/kg/day) or saline for 14 days. Offspring were killed in P180 and immunohistochemistry and Western blot analysis were carried out. Significance data had p<0.05. Adult NIC offspring showed more intense NPY staining in the paraventricular nucleus (PVN) (+21%) and increased number of POMC-positive cells in the: arcuate nucleus (+33%), as an increase in fiber density of α-MSH in PVN (+85%). However, the number of CART-positive cells was reduced in the PVN (-25%). CRH staining was more intense in NIC offspring (+136%). Orexins and AgRP were not altered. Thus, maternal nicotine exposure changes hypothalamic neuropeptides in the adult progeny that is partially compatible with leptin resistance.

Early weaning is associated with higher neuropeptide Y (NPY) and lower cocaine- and amphetamine-regulated transcript (CART) expressions in the paraventricular nucleus (PVN) in adulthood.

The interruption of lactation for a short period, without the use of pharmacological substances or maternal separation, causes offspring malnutrition and hypoleptinaemia and programmes for metabolic disorders such as higher body weight and adiposity, hyperphagia, hyperleptinaemia and central leptin resistance in adulthood. Here, in order to clarify the mechanisms underlying the phenotype observed in adult early-weaned (EW) rats, we studied the expression of neuropeptide Y (NPY), agouti-related peptide (AgRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) in different hypothalamic nuclei by immunohistochemistry and Western blot. In the EW group, the teats of lactating rats were blocked with a bandage to interrupt lactation during the last 3 d, while control pups had free access to milk throughout the entire lactation period. At age 180 d, EW offspring showed higher NPY staining in the paraventricular nucleus (PVN), as well as NPY protein content (+68 %) in total hypothalamus than control ones. AgRP showed no changes in staining or Western blot. POMC content was not affected; however, its distribution pattern was altered. CART-positive cells of EW offspring had lower immunoreactivity associated with reduced cell number in the PVN and lower protein content ( - 38 %) in total hypothalamus. The present data indicate that precocious weaning can imprint the neuronal circuitry, especially in the PVN, and cause a long-term effect on the expression of specific orexigenic and anorexigenic neuropeptides, such as NPY and CART, that can be caused by leptin resistance and are coherent with the hyperphagia observed in these animals.

Adipocyte morphology and leptin signaling in rat offspring from mothers supplemented with flaxseed during lactation.

OBJECTIVE: We have recently shown that maternal flaxseed supplementation during lactation induces insulin resistance in adult offspring. Here, we studied the effects of maternal dietary flaxseed during lactation on adipocyte morphology and leptin signaling in the hypothalamic-pituitary-thyroid axis as well as on behavioral traits in the adult progeny. METHODS: Lactating rats were fed a control (C) diet or a diet with 25% flaxseed (F). After weaning, pups received a standard diet until postnatal day (PN) 180. Male offspring were killed at PN21 and 180. Data were considered significant at P < 0.05. RESULTS: Weaned F rats presented a lower total and subcutaneous fat mass and higher subcutaneous adipocyte area (+48%), but at adulthood they presented higher subcutaneous and visceral adipocyte areas (+40% and 1.9-fold increase, respectively), with no change in body fat mass. At PN21, F pups had hyperleptinemia (+69%), lower T(3) (-33%), higher TSH (2.1-fold increase), higher pituitary leptin receptor (Ob-R, +11%), signal transducer and activator of transcription 3 (STAT3, +21%), and phosphorylated-STAT3 (p-STAT3, +77%) protein content. Adult F offspring only showed lower T(4) (-28%) and higher thyroid Ob-R (+52%) expression. Maternal flaxseed intake during lactation did not result in behavioral changes in the adult offspring. CONCLUSIONS: Maternal flaxseed supplementation decreases offspring adiposity and increases pituitary leptin signaling at weaning, but it induces hypertrophic adipocytes and higher thyroid leptin receptor in adulthood. The present data suggest that extensive use of flaxseed during lactation is undesirable.

Acute administration of vinpocetine, a phosphodiesterase type 1 inhibitor, ameliorates hyperactivity in a mice model of fetal alcohol spectrum disorder.

BACKGROUND: Maternal alcohol use during pregnancy causes a continuum of long-lasting disabilities in the offspring, commonly referred to as fetal alcohol spectrum disorder (FASD). Attention-deficit/hyperactivity disorder (ADHD) is possibly the most common behavioral problem in children with FASD and devising strategies that ameliorate this condition has great clinical relevance. Studies in rodent models of ADHD and FASD suggest that impairments in the cAMP signaling cascade contribute to the hyperactivity phenotype. In this work, we investigated whether the cAMP levels are affected in a long-lasting manner by ethanol exposure during the third trimester equivalent period of human gestation and whether the acute administration of the PDE1 inhibitor vinpocetine ameliorates the ethanol-induced hyperactivity. METHODS: From postnatal day (P) 2 to P8, Swiss mice either received ethanol (5g/kg i.p.) or saline every other day. At P30, the animals either received vinpocetine (20mg/kg or 10mg/kg i.p.) or vehicle 4h before being tested in the open field. After the test, frontal cerebral cortices and hippocampi were dissected and collected for assessment of cAMP levels. RESULTS: Early alcohol exposure significantly increased locomotor activity in the open field and reduced cAMP levels in the hippocampus. The acute treatment of ethanol-exposed animals with 20mg/kg of vinpocetine restored both their locomotor activity and cAMP levels to control levels. CONCLUSIONS: These data lend support to the idea that cAMP signaling system contribute to the hyperactivity induced by developmental alcohol exposure and provide evidence for the potential therapeutic use of vinpocetine in FASD.