Isocaloric Sucrose Research Articles

Ventral Tegmental Area Amylin Receptor Activation Differentially Modulates Mesolimbic Dopamine Signaling in Response to Fat versus Sugar.

Amylin, a pancreatic hormone that is cosecreted with insulin, has been highlighted as a potential treatment target for obesity. Amylin receptors are distributed widely throughout the brain and are coexpressed on mesolimbic dopamine neurons. Activation of amylin receptors is known to reduce food intake, but the neurochemical mechanisms behind this remain to be elucidated. Amylin receptor activation in the ventral tegmental area (VTA), a key dopaminergic nucleus in the mesolimbic reward system, has a potent ability to suppress intake of palatable fat and sugar solutions. Although previous work has demonstrated that VTA amylin receptor activation can dampen mesolimbic dopamine signaling elicited by random delivery of sucrose, whether this is also the case for fat remains unknown. Herein we tested the hypothesis that amylin receptor activation in the VTA of male rats would attenuate dopamine signaling in the nucleus accumbens core in response to random intraoral delivery of either fat or sugar solutions. Results show that fat solution produces a greater potentiation of accumbens dopamine than an isocaloric sucrose solution. Moreover, activation of VTA amylin receptors elicits a more robust suppression of accumbens dopamine signaling in response to fat solution than to sucrose. Taken together these results shed new light on the amylin system as a therapeutic target for obesity and emphasize the reinforcing nature of high-fat/high-sugar diets.

A high sucrose detection threshold is associated with increased energy intake and improved post-prandial glucose response independent of the sweetness intensity of isocaloric sucrose solutions

Several studies proposed a role for the sweet taste receptor in energy intake and blood glucose regulation, but little is yet known about the impact of the individual sweet taste perception. Here, we found in a cross-over human intervention study with 29 male participants that modulating the sweetness of an isocaloric sucrose solution did not influence postprandial plasma concentrations of blood glucose and associated hormones over 120 min and 2 h post-load energy intake. Independent of the sweetness of the test solution, tests persons with a higher sucrose detection threshold had an average of 402 ± 78.8 kcal (39 ± 21%) higher energy intake and a higher glucose/insulin ratio, combined with a higher liking for sweet tasting food, than the test persons of the low threshold group. The body composition suggested a higher fat-free mass in the high threshold group that may have influenced energy intake and post-prandial glucose responses.

Comparable metabolic effects of isocaloric sucrose and glucose solutions in rats

Much of the global increase in sugar intake is attributable to rising consumption of sugar-sweetened beverages (SSBs). Because people compensate poorly for liquid calories, SSB consumption increases total energy intake, raising the risk of harmful metabolic effects in addition to possible effects of sugars per se. Glucose and fructose, the constituent sugars in sucrose, can exert distinct effects on metabolism and also differ in their satiating properties, suggesting that compensation for the calories in these sugars may also vary. In light of claims that the fructose within sucrose is particularly harmful, the present study compared the effects of giving rats access to either a sucrose or an isoenergetic glucose solution. Adult male rats were fed standard chow and water supplemented with 95 ml of 10% glucose (Glucose group; n = 10), 9% sucrose solution (Sucrose group; n = 10) or water only (Control group; n = 10) daily for 7 weeks. Sugar-fed groups had higher total energy intakes than the Control group, but the extent of this incomplete compensation did not vary between Sucrose and Glucose groups. In a short-term compensation test, sugar groups were less sensitive to the effects of a sweet pre-meal, with no differences between the Glucose and Sucrose groups. Relative to water, both sugars reduced insulin sensitivity after 4 weeks on the diets and elevated fat mass at 7 weeks. Results suggest that sucrose and glucose induce comparable metabolic impairments and alter the homeostatic regulation of food intake even under conditions where daily access is capped.

Sucrose consumption alters steroid and dopamine signalling in the female rat brain.

Sucrose consumption is associated with type 2 diabetes, cardiovascular disease, and cognitive deficits. Sucrose intake during pregnancy might have particularly prominent effects on metabolic, endocrine, and neural physiology. It remains unclear how consumption of sucrose affects parous females, especially in brain circuits that mediate food consumption and reward processing. Here, we examine whether a human-relevant level of sucrose before, during, and after pregnancy (17-18 weeks total) influences metabolic and neuroendocrine physiology in female rats. Females were fed either a control diet or a macronutrient-matched, isocaloric sucrose diet (25% of kcal from sucrose). Metabolically, sucrose impairs glucose tolerance, increases liver lipids, and increases a marker of adipose inflammation, but has no effect on body weight or overall visceral adiposity. Sucrose also decreases corticosterone levels in serum but not in the brain. Sucrose increases progesterone levels in serum and in the brain and increases the brain:serum ratio of progesterone in the mesocorticolimbic system and hypothalamus. These data suggest a dysregulation of systemic and local steroid signalling. Moreover, sucrose decreases tyrosine hydroxylase (TH), a catecholamine-synthetic enzyme, in the medial prefrontal cortex. Finally, sucrose consumption alters the expression pattern of FOSB, a marker of phasic dopamine signalling, in the nucleus accumbens. Overall, chronic consumption of sucrose at a human-relevant level alters metabolism, steroid levels, and brain dopamine signalling in a female rat model.

A 5‐HT2A/2C receptor agonist, 1‐(2,5‐dimethoxy‐4‐iodophenyl)‐2‐aminopropane, mitigates developmental neurotoxicity of ethanol to serotonergic neurons

Prenatal ethanol exposure causes the reduction of serotonergic (5-HTergic) neurons in the midbrain raphe nuclei. In the present study, we examined whether an activation of signaling via 5-HT2A and 5-HT2C receptors during the fetal period is able to prevent the reduction of 5-HTergic neurons induced by prenatal ethanol exposure. Pregnant Sprague-Dawley rats were given a liquid diet containing 2.5 to 5.0% (w/v) ethanol on gestational days (GDs) 10 to 20 (Et). As a pair-fed control, other pregnant rats were fed the same liquid diet except that the ethanol was replaced by isocaloric sucrose (Pf). Each Et and Pf group was subdivided into two groups; one of the groups was treated with 1 mg/kg (i.p.) of 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), an agonist for 5-HT2A/2C receptors, during GDs 13 to 19 (Et-DOI or Pf-DOI), and another was injected with saline vehicle only (Et-Sal or Pf-Sal). Their fetuses were removed by cesarean section on GD 19 or 20, and fetal brains were collected. An immunohistological examination of 5-HTergic neurons in the fetuses on embryonic day 20 using an antibody against tryptophan hydroxylase revealed that the number of 5-HTergic neurons in the midbrain raphe nuclei was significantly reduced in the Et-Sal fetuses compared to that of the Pf-Sal and Pf-DOI fetuses, whereas there were no significant differences between Et-DOI and each Pf control. Thus, we concluded that the reduction of 5-HTergic neurons that resulted in prenatal ethanol exposure could be alleviated by the enhancement of signaling via 5-HT2A/2C receptors during the fetal period.

Modeling Symptoms of Attention-Deficit Hyperactivity Disorder in a Rat Model of Fetal Alcohol Syndrome.

Several studies indicate the similarity between the symptoms of fetal alcohol syndrome and attention-deficit hyperactivity disorder (ADHD). This study hypothesized that prenatal exposure to ethanol (EtOH) can be used as an animal model of ADHD in Wistar rats. At the first stage of the study, alcohol was delivered to the pregnant dams (237-252 g) by intra-gastric route throughout Gestation Days 8-20 at a dose of 6 g/kg/day. Untreated control group with isocaloric sucrose intubation was also included. Of the 16 male pups (174-180 g), 8 were in the fetal alcohol effects (FAE) group and 8 were in the untreated control group. Subjects went through behavior shaping, discrimination learning and reversal learning. Number of sessions to learn the tasks, response frequency to inhibitory (S-) and excitatory (S+) stimulus features, response latency and inter-response time (IRT) were measured. Significant differences were obtained on only the reversal task. Rats with FAE needed greater number of sessions to learn the reversal task, and they had a higher frequency of incorrect responses in specifically the latter part of the sessions. Our results suggest that reversal learning of FAE rats exhibits deficit in the inhibition of pre-learned responses. Responses behaviorally mimicked attention deficit and impulsivity symptoms of human ADHD. However, the experimental design of the study was not conducive to hyperactivity. Accordingly, rats with FEA can be an alternative to other models since it is not, for example, based on a symptom that is atypical (such as hypertension) to ADHD. Significant difference was obtained in a reversal task between male rats prenatally exposed to ethanol and matched controls. The greater number of sessions for learning and higher frequency of incorrect responses behaviorally mimicked symptoms of ADHD, suggesting that rats with fetal ethanol effects can serve as a useful animal model.

Chronic Binge Alcohol Administration Increases Intestinal T-Cell Proliferation and Turnover in Rhesus Macaques.

Alcohol use results in changes in intestinal epithelial cell turnover and microbial translocation, yet less is known about the consequences on intestinal lymphocytes in the gut. Here, we compared T-cell subsets in the intestine of macaques before and after 3 months of chronic alcohol administration to examine the effects of alcohol on intestinal T-cell subsets. Rhesus macaques received either alcohol or isocaloric sucrose as a control treatment daily over a 3-month period via indwelling gastric catheters. Intestinal lymphocyte subsets were identified in biopsy samples by flow cytometry. Twenty-four hours prior to sampling, animals were inoculated with bromo-deoxyuridine (BrdU) to assess lymphocyte proliferation. Immunohistochemistry was performed on tissue samples to quantitate CD3+ cells. Animals receiving alcohol had increased rates of intestinal T-cell turnover of both CD4+ and CD8+ T cells as reflected by increased BrdU incorporation. However, absolute numbers of T cells were decreased in intestinal tissues as evidenced by immunohistochemistry for total CD3 expression per mm(2) intestinal lamina propria in tissue sections. Combining immunohistochemistry and flow cytometry data showed that the absolute numbers of CD8+ T cells were significantly decreased, whereas absolute numbers of total CD4+ T cells were minimally decreased. Collectively, these data indicate that alcohol exposure to the small intestine results in marked loss of CD3+ T cells, accompanied by marked increases in CD4+ and CD8+ T-cell proliferation and turnover, which we speculate is an attempt to maintain stable numbers of T cells in tissues. This suggests that alcohol results in accelerated T-cell turnover in the gut, which may contribute to premature T-cell senescence. Further, these data indicate that chronic alcohol administration results in increased levels of HIV target cells (proliferating CD4+ T cells) that may support higher levels of HIV replication in intestinal tissues.

Hippocampal neuron populations are reduced in vervet monkeys with fetal alcohol exposure.

Prenatal exposure to beverage alcohol is a major cause of mild mental retardation and developmental delay. In nonendangered alcohol-preferring vervet monkeys, we modeled the most common nondysmorphic form of fetal alcohol syndrome disorder with voluntary drinking during the third trimester of pregnancy. Here, we report significant numerical reductions in the principal hippocampal neurons of fetal alcohol-exposed (FAE) offspring, as compared to age-matched, similarly housed conspecifics with isocaloric sucrose exposure. These deficits, particularly marked in CA1 and CA3, are present neonatally and persist through infancy (5 months) and juvenile (2 years) stages. Although the volumes of hippocampal subdivisions in FAE animals are not atypical at birth, by age 2, they are only 65–70% of those estimated in age-matched controls. These data suggest that moderate, naturalistic alcohol consumption during late pregnancy results in a stable loss of hippocampal neurons and a progressive reduction of hippocampal volume. © 2015 The Authors. Developmental Psychobiology Published by Wiley Periodicals, Inc. Dev Psychobiol 57:470–485, 2015.

Chronic binge alcohol (CBA) decreases miR‐206 expression in the skeletal muscle of Simian Immunodeficiency Virus (SIV)‐infected macaques

Studies using a non-human primate model of SIV infection have demonstrated that myoblasts isolated from CBA/SIV macaques have altered myogenic gene expression and decreased myoblast differentiation potential, suggesting impaired skeletal muscle (SKM) regeneration as a mechanism contributing to loss of SKM at end stage SIV. We hypothesized that the altered SKM milieu in CBA/SIV macaques dysregulates SKM specific microRNAs that regulate gene transcription necessary for myogenesis. Histone deacetylase 4 (HDAC4) negatively regulates myogenesis by associating with myocyte enhancer factor 2 (MEF2) and is a target of miR-206. CBA or isocaloric sucrose (SUC) were administered daily via a gastric catheter to male rhesus macaques beginning 3 mo. prior to SIV infection and continued throughout the duration of study. At ten weeks post-SIV infection, daily administration of antiretroviral therapy (ART; tenofovir and emtricitabine) was initiated in a subset of both SUC/SIV and CBA/SIV groups and continued for the duration of the study. SKM was obtained at necropsy (~11 mo. post-SIV) from SUC/SIV/ART± and CBA/SIV/ART± macaques. SKM of CBA/SIV macaques showed significantly decreased expression of miR-206 and MEF2C mRNA compared to SKM of SUC/SIV irrespective of ART. In contrast, SKM of CBA/SIV macaques showed increased mRNA expression of HDAC4 compared to SUC/SIV irrespective of ART. These results suggest that decreased miR-206 in CBA/SIV macaques favors upregulation of HDAC4, which represses MEF2C potentially contributing to impaired myogenesis. Future studies will verify the functional implications of the altered myomiR profile in myoblasts and its contribution to impaired SKM regeneration in CBA/SIV macaques.

Impulsive choice predicts anxiety-like behavior, but not alcohol or sucrose consumption, in male Long-Evans rats.

Prior human research indicates robust, positive relations between impulsive choice (i.e., preference for smaller, immediate over larger, delayed rewards) and alcohol use disorders. However, varied findings in the nonhuman literature reveal a relatively ambiguous relation between impulsive choice and alcohol consumption in rodents. In addition, few rodent studies have investigated potential relations between impulsive choice and common covariates of alcohol consumption (e.g., avidity for sweet substances or anxiety-like behavior). Ninety-two male Long-Evans rats completed an impulsive-choice task. From this larger sample, extreme high- and low-impulsive groups (n=30 each) were retained for further testing. In separate tests, subsequent open-field behavior and consumption of oral alcohol (12% w/v) and isocaloric sucrose were examined. Impulsive choice was then retested to examine whether behavior remained stable over the course of the experiment. No significant relations emerged between impulsive choice and either alcohol or sucrose consumption. However, impulsive choice predicted greater anxiety-like behavior (avoidance of the center field, defecation) in the open-field test. In turn, greater anxiety predicted lower alcohol and sucrose consumption. Finally, choice remained generally stable across the experiment, although high-impulsive rats tended toward less impulsive choice in the retest. Although impulsive choice and alcohol consumption appear to share some variance with anxiety-like behavior, the present data offer no support for a relation between impulsive choice and alcohol consumption in Long-Evans rats. Together with mixed rodent data from prior reports, these findings attenuate cross-species comparisons to human relations between impulsive choice and alcohol use disorders.

Chronic Binge Alcohol Administration in Simian Immunodeficiency Virus‐Infected Rhesus Macaques Modulates Pre‐Frontal Cortex Expression of Brain‐Derived Neurotrophic Factor and Microtubule‐Associated Protein 2

Persons living with HIV/AIDS have a higher incidence of alcohol use and abuse. Previous studies by our group revealed that chronic binge alcohol (CBA) administration unmasks cognitive deficits in SIV-infected rhesus macaques. Chronic alcohol abuse and HIV infection result in loss of neurotrophic factors and neurons. We hypothesized that CBA administration would synergize with SIV to produce greater suppression of neurotrophic factor expression compared to SUC/SIV. Rhesus macaques were fitted with an intra-gastric catheter for delivery of alcohol (CBA, n = 7) or isocaloric sucrose (SUC, n = 7) for the duration of the experiment. Macaques were infected with SIVmac251 three months after initiation of CBA or SUC, one SUC animal was not infected. Macaques were euthanized when end-stage criteria were met (∼4 or 18 months post-inoculation), brains were excised and dissected. Pre-frontal cortex (PFC), caudate (Cd) and hippocampus (Hp) were used for analysis of tissue viral load and gene expression of BDNF and MAP2. Viral load was not significantly different in CBA animals or between brain regions. PFC was the only brain in which viral load was above the limit of detection in all animals. BDNF expression was lower in CBA/SIV only in the PFC (p=NS). MAP2 expression was lower in PFC and Cd (p=NS). Gene expression of MAP2 was positively correlated with BDNF in the PFC (p<0.01), Cd (p<0.01) and Hp (p=0.03). The results suggest that the PFC is most susceptible to combined SIV and CBA insult. Supported by AA07577, AA09803, AA11290.

Chronic Binge Alcohol (CBA) Decreases Skeletal Muscle Oxidative Capacity in Simian Immunodeficiency Virus (SIV)‐Infected Macaques

Chronic HIV infection is associated with insulin resistance and increased lipodystrophy. Skeletal muscle (SKM) represents a major site for glucose and lipid oxidation. Acute and chronic alcohol exposure inhibits skeletal muscle glucose metabolism and potentially promotes insulin resistance. We sought to determine the effects of daily CBA or isocaloric sucrose (SUC) administration to male SIV-infected rhesus macaques on SKM muscle fiber type and oxidative capacity. SKM samples (quadriceps) were collected at necropsy after 11 months of SIV infection from CBA/SIV (n=5) or SUC/SIV (n=3) macaques. Serial cross sections (10 μm) were stained for myosin ATPase to determine fiber type population and succinate dehydrogenase (SDH) to measure oxidative capacity. Both SUC/SIV and CBA/SIV animals had decreased (33.2 and 28.2%) number of type 1 (oxidative) fibers and a larger proportion of type 2b (glycolytic) fibers compared to naïve uninfected animals (42%) (n=2). SDH activity, measured by optical density, was significantly lower in the type 1 fibers of both SUC/SIV (OD=87.8) and CBA/SIV (OD=90.7) when compared to controls (OD=120.7). Analysis of SDH activity across all muscle fibers demonstrated a significant reduction in total oxidative capacity in CBA/SIV (OD=146.6) compared to naïve (OD=268.3) and SUC/SIV (OD=195.4) groups. These results demonstrate a reduction in the oxidative capacity of SKM fibers in SIV-infected animals that is further exacerbated by CBA. This research was supported by grants AA07577, AA09803 and AA11290 from the NIAAA/NIH

Post-Exercise Protein Trial: Interactions between Diet and Exercise (PEPTIDE): study protocol for randomized controlled trial.

BackgroundPerforming regular exercise is known to manifest a number of health benefits that mainly relate to cardiovascular and muscular adaptations to allow for greater oxygen extraction and utilization. There is increasing evidence that nutrient intake can affect the adaptive response to a single exercise bout, and that protein feeding is important to facilitate this process. Thus, the exercise-nutrient interaction may potentially lead to a greater response to training. The role of post-exercise protein ingestion in enhancing the effects of running-based endurance exercise training relative to energy-matched carbohydrate intervention remains to be established. Additionally, the influence of immediate versus overnight protein ingestion in mediating these training effects is currently unknown. The current protocol aims to establish whether post-exercise nutrient intake and timing would influence the magnitude of improvements during a prescribed endurance training program.Methods/DesignThe project involves two phases with each involving two treatment arms applied in a randomized investigator-participant double-blind parallel group design. For each treatment, participants will be required to undergo six weeks of running-based endurance training. Immediately post-exercise, participants will be prescribed solutions providing 0.4 grams per kilogram of body mass (g · kg−1) of whey protein hydrolysate plus 0.4 g · kg−1 sucrose, relative to an isocaloric sucrose control (0.8 g · kg−1; Phase I). In Phase II, identical protein supplements will be provided (0.4 + 0.4 g · kg−1 · h−1 of whey protein hydrolysate and sucrose, respectively), with the timing of ingestion manipulated to compare immediate versus overnight recovery feedings. Anthropometric, expired gas, venous blood and muscle biopsy samples will be obtained at baseline and following the six-week training period.DiscussionBy investigating the role of nutrition in enhancing the effects of endurance exercise training, we will provide novel insight regarding nutrient-exercise interactions and the potential to help and develop effective methods to maximize health or performance outcomes in response to regular exercise.Trial registrationCurrent Controlled Trials registration number: ISRCTN27312291 (date assigned: 4 December 2013). The first participant was randomized on 11 December 2013.

Impulsive choice, alcohol consumption, and pre-exposure to delayed rewards: II. Potential mechanisms.

In a prior study (Stein et al., 2013), we reported that rats pre-exposed to delayed rewards made fewer impulsive choices, but consumed more alcohol (12% wt/vol), than rats pre-exposed to immediate rewards. To understand the mechanisms that produced these findings, we again pre-exposed rats to either delayed (17.5 s; n=32) or immediate (n=30) rewards. In posttests, delay-exposed rats made significantly fewer impulsive choices at 15- and 30-s delays to a larger, later food reward than the immediacy-exposed comparison group. Behavior in an open-field test provided little evidence of differential stress exposure between groups. Further, consumption of either 12% alcohol or isocaloric sucrose in subsequent tests did not differ between groups. Because Stein et al. introduced alcohol concentration gradually (3-12%), we speculate that their group differences in 12% alcohol consumption were not determined by alcohol's pharmacological effects, but by another variable (e.g., taste) that was preserved as an artifact from lower concentrations. We conclude that pre-exposure to delayed rewards generalizes beyond the pre-exposure delay; however, this same experimental variable does not robustly influence alcohol consumption.

Chronic binge alcohol consumption does not diminish effectiveness of continuous antiretroviral suppression of viral load in simian immunodeficiency virus-infected macaques.

Alcohol use disorders (AUDs) are a frequent comorbidity in a large percentage of people living with HIV/AIDS (PLWHA). PLWHA with comorbid AUDs are consistently found to perform poorly at most levels of the HIV treatment cascade, resulting in a higher likelihood of virologic nonsuppression. This has been partly attributed to lower rates of persistence with and adherence to antiretroviral therapies (ART). Focus groups of in-care PLWHA identify the need to suspend ART on drinking days because of the potential for toxicity and/or lack of therapeutic effectiveness. The aim of this study was to examine whether chronic binge alcohol (CBA) consumption decreases the effectiveness of uninterrupted ART, specifically that of nucleoside reverse-transcriptase inhibitors (NRTI) tenofovir and emtricitabine in suppressing viral replication, or results in drug toxicity in simian immunodeficiency virus (SIV)-infected rhesus macaques. Daily CBA or isocaloric sucrose (SUC) administration was initiated 3 months prior to intrarectal SIVmac251 inoculation and continued throughout the study period. ART was initiated 2.5 months after SIV infection and continued through the study period. CBA administration did not prevent or delay the ART-mediated reduction in viral load. Following ART, circulating levels of total protein and creatinine were significantly higher than baseline values in both SUC- and CBA-treated animals, but still within a normal range. No evidence of ART toxicity was observed in either CBA- or SUC-administered macaques. These findings indicate that CBA does not attenuate effectiveness of NRTI suppression of viral load, nor does it appear to interact with NRTI to produce toxicity during the initial 2 months of treatment. We conclude that while efforts to reduce AUD in PLWHA should be a priority, counseling on the importance of adherence to ART even on drinking days should also be promoted.

The effects of chronic binge alcohol on the genital microenvironment of simian immunodeficiency virus-infected female rhesus macaques.

Alcohol abuse is a widespread problem among those at risk for and living with HIV and can impact transmission and disease progression. In this study we sought to use the simian immunodeficiency virus (SIV)-macaque model to evaluate the immunological and virological changes in the genital microenvironment of females exposed to chronic alcohol. Female rhesus macaques were treated with alcohol (n=6) or isocaloric sucrose (n=6) for 3 months and then inoculated with SIVmac251. To assess the effects of chronic alcohol on SIV disease and the genital microenvironment, we quantified plasma and genital SIV levels, measured inflammatory cells in genital fluids, and characterized microbial flora by gram stains over 10 weeks post-SIV infection. Following 3 months of alcohol/sucrose treatment, significant differences were observed in the vaginal microenvironment of alcohol-treated animals as compared to controls. Microbial flora of alcohol-treated animals had decreased levels of lactobacillus morphotypes and increased levels of gram-positive cocci relative to sucrose controls. Alcohol-treated animals were also more likely to have white blood cells in vaginal fluids prior to SIV inoculation, which persisted through viral set point. Similar levels of cell-free SIV were observed in plasma and vaginal fluids of both groups, but alcohol-treated animals had a higher incidence and levels of cell-associated SIV shed in vaginal secretions. Chronic alcohol treatment negatively impacts the genital microenvironment prior to and over the course of SIV infection and may increase the risk of genital virus shedding and transmission.

Enriched environment attenuates changes in water-maze performance and BDNF level caused by prenatal alcohol exposure.

Prenatal exposure to alcohol can result in fetal alcohol syndrome (FAS), characterized by significant changes in the physiology, structural plasticity of hippocampal function, including long-term deficits in learning and memory. Environmental enrichment has long been known to improve motor and cognitive function levels, causes several neurochemical and morphological alterations in the brain. Therefore, the effects of environmental enrichment on the neurobehavioral and neurotrophic changes in mice exposed prenatally to alcohol were investigated in this study. The pregnant dams were given 25 % ethanol (w/v) or isocaloric sucrose by liquid diet from gestation day 7 to 20. After weaning on postnatal day 28, offspring were exposed to standard cage (CC, CFAS) or enriched living conditions (CE, EFAS) for 8 weeks. Neurobehavioral studies both on hippocampus-dependent spatial learning and place and cue learning strategy, a striatum-dependent test, were measured by the Morris water maze task. Moreover, the reverse-transcriptase polymerase chain reaction (RT-PCR) technique was also used in order to study the expression of brain-derived neurotrophic factor (BDNF) level in both the hippocampus and striatum of mice. Neurobehavioral studies show that animals exposed prenatally to alcohol were impaired as shown in both hippocampal-dependent spatial/place and striatal-dependent response/cue learning tests. Moreover, the levels of BDNF expression both in the hippocampus and striatum of mice were also decreased. Interestingly, environmental enrichment can ameliorate the effects of prenatal alcohol exposure both on the neurobehavioral and neurotrophic levels. These observations indicated that enriched environment attenuated memory impairment of prenatal alcohol exposure both in hippocampal and striatal circuitry.

Chronic binge alcohol consumption alters myogenic gene expression and reduces in vitro myogenic differentiation potential of myoblasts from rhesus macaques

Chronic alcohol abuse is associated with skeletal muscle myopathy. Previously, we demonstrated that chronic binge alcohol (CBA) consumption by rhesus macaques accentuates skeletal muscle wasting at end-stage of simian immunodeficiency virus (SIV) infection. A proinflammatory, prooxidative milieu and enhanced ubiquitin proteasome activity were identified as possible mechanisms leading to loss of skeletal muscle. The possibility that impaired regenerative capacity, as reflected by the ability of myoblasts derived from satellite cell (SCs) to differentiate into myotubes has not been examined. We hypothesized that the inflammation and oxidative stress in skeletal muscle from CBA animals impair the differentiation capacity of myoblasts to form new myofibers in in vitro assays. We isolated primary myoblasts from the quadriceps femoris of rhesus macaques that were administered CBA or isocaloric sucrose (SUC) for 19 mo. Proliferation and differentiation potential of cultured myoblasts were examined in vitro. Myoblasts from the CBA group had significantly reduced PAX7, MYOD1, MYOG, MYF5, and MEF2C expression. This was associated with decreased myotube formation as evidenced by Jenner-Giemsa staining and myonuclei fusion index. No significant difference in the proliferative ability, cell cycle distribution, or autophagy was detected between myoblasts isolated from CBA and SUC groups. Together, these results reflect marked dysregulation of myoblast myogenic gene expression and myotube formation, which we interpret as evidence of impaired skeletal muscle regenerative capacity in CBA-administered macaques. The contribution of this mechanism to alcoholic myopathy warrants further investigation.

Effect of Bacterial Pneumonia on Lung Simian Immunodeficiency Virus (SIV) Replication in Alcohol Consuming SIV‐Infected Rhesus Macaques

Opportunistic infections in human immunodeficiency virus (HIV)-infected persons have been shown to increase the rate of HIV replication. In populations where prophylaxis against Pneumocystis pneumonia is utilized, bacterial pneumonia is now the leading cause of lower respiratory tract infection in HIV+ patients. Our prior studies have shown that chronic alcohol consumption in demarcated simian immunodeficiency virus (SIV)-infected rhesus macaques increases plasma viral load set point and accelerates progression to end-stage acquired immune deficiency syndrome. While chronic alcohol abuse is well known to increase the incidence and severity of bacterial pneumonia, the impact of alcohol consumption on local and systemic SIV/HIV burden during lung infection is unknown. Therefore, we utilized the macaque SIV infection model to examine the effect of chronic ethanol (EtOH) feeding on SIV burden during the course of pulmonary infection with Streptococcus pneumoniae, the most commonly identified etiology of bacterial pneumonia in HIV+ and HIV- persons in developed countries. Alcohol was administered starting 3months before SIVmac251 inoculation to the end of the study via an indwelling intragastric catheter to achieve a plasma alcohol concentration of 50 to 60mM. Control animals received isocaloric sucrose. Four months after SIV infection, the right lung was inoculated with 2×10(6) CFU S.pneumoniae. Leukocyte recruitment into the lung, pulmonary bacterial clearance, and clinical course were similar between EtOH and control groups. While plasma SIV viral load was similar between groups postpneumonia, chronic EtOH-fed macaques showed a prolonged increase in SIV RNA in bronchoalveolar lavage fluid. Alveolar macrophages isolated from EtOH-fed macaques 1day post-pneumonia showed greater nuclear factor kappa beta (NF-κB) activation. This study indicates that chronic EtOH feeding results in enhanced local, but not systemic, SIV replication following pneumococcal pneumonia. Increased NF-κB activity in the setting of chronic EtOH ingestion may play a mechanistic role in this observation.

Intensity and duration of chronic ethanol exposure is critical for subsequent escalation of voluntary ethanol drinking in mice.

Excessive alcohol drinking continues to be an important health problem. Recent studies from our laboratory and others have demonstrated that animal models of ethanol dependence and relapse can contribute to understanding factors that contribute to excessive drinking. In this study, we tested the hypothesis that the amount and duration of ethanol exposure is critical for promoting the escalation in drinking by mice given access to ethanol in a limited access paradigm. We used several methods of chronic intermittent ethanol exposure in male C57BL/6J mice that would vary in the amount and duration of exposure to ethanol as indicated by blood ethanol concentrations (BEC). After establishing baseline drinking in the mice using a 2 hours, 2 bottle choice drinking paradigm, each study involved alternating between periods of ethanol exposure and periods of limited access to ethanol (1 cycle) for a total of 3 cycles. In Study 1, mice were allowed extended access (16 hours) to ethanol for oral consumption or remained in the home cage. In Study 2, the ethanol exposure consisted of intragastric gavage of increasing doses of ethanol or isocaloric sucrose as the control. Study 3 compared intragastric gavage combined with pyrazole, an alcohol dehydrogenase inhibitor, with vapor inhalation of ethanol using procedures known to lead to increased drinking in mice. Finally, Study 4 was a retrospective review of several studies conducted in our laboratory using inhalation procedures. The retrospective review encompassed a range of postvapor chamber BEC values and ethanol intakes that would allow a relationship between increased drinking and BEC to be examined. Allowing mice to drink for longer periods of time did not cause increased drinking in subsequent limited access sessions. Likewise, gastric intubation of ethanol which produced high BEC (>300 mg/dl) with or without pyrazole did not increase drinking. Only the vapor inhalation procedure, which was associated with sustained BEC above 175 mg/dl for the entire exposure period resulted in increased drinking. The retrospective study provided further evidence that sustained BEC levels above 175 mg/dl was critical to the escalation in drinking. We found that the intensity (amount) and duration of ethanol exposure, indexed by BEC, is critical to produce increased drinking in mice. Specifically, BEC must regularly exceed 175 mg/dl for the escalation in drinking to occur. Future studies will examine neurobiological adaptations that may underlie the increased drinking behavior caused by chronic intermittent ethanol exposure.