Potential therapeutics for effort-related motivational dysfunction: assessing novel atypical dopamine transport inhibitors

People with depression and other neuropsychiatric disorders can experience motivational dysfunctions such as fatigue and anergia, which involve reduced exertion of effort in goal-directed activity. To model effort-related motivational dysfunction, effort-based choice tasks can be used, in which rats can select between obtaining a preferred reinforcer by high exertion of effort vs. a low effort/less preferred option. Preclinical data indicate that dopamine transport (DAT) inhibitors can reverse pharmacologically-induced low-effort biases and increase selection of high-effort options in effort-based choice tasks. Although classical DAT blockers like cocaine can produce undesirable effects such as liability for misuse and psychotic reactions, not all DAT inhibitors have the same neurochemical profile. The current study characterized the effort-related effects of novel DAT inhibitors that are modafinil analogs and have a range of binding profiles and neurochemical actions (JJC8-088, JJC8-089, RDS3-094, and JJC8-091) by using two different effort-related choice behavior tasks in male Sprague-Dawley rats. JJC8-088, JJC8-089, and RDS3-094 significantly reversed the low-effort bias induced by the VMAT-2 inhibitor tetrabenazine, increasing selection of high-effort fixed ratio 5 lever pressing vs. chow intake. In addition, JJC8-089 reversed the effects of tetrabenazine in female rats. JJC8-088 and JJC8-089 also increased selection of high-effort progressive ratio responding in a choice task. However, JJC8-091 failed to produce these outcomes, potentially due to its unique pharmacological profile (i.e., binding to an occluded conformation of DAT). Assessment of a broad range of DAT inhibitors with different neurochemical characteristics may lead to the identification of compounds that are useful for treating motivational dysfunction in humans.

The Neurobiology of Activational Aspects of Motivation: Exertion of Effort, Effort-Based Decision Making, and the Role of Dopamine

Motivational processes are complex and multifaceted, with both directional and activational aspects. Behavioral activation and exertion of effort are functions that enable organisms to overcome obstacles separating them from significant outcomes. In a complex environment, organisms make cost/benefit decisions, assessing work-related response costs and reinforcer preference. Animal studies have challenged the general idea that dopamine (DA) is best viewed as the reward transmitter and instead have illustrated the involvement of DA in activational and effort-related processes. Mesocorticolimbic DA is a key component of the effort-related motivational circuitry that includes multiple neurotransmitters and brain areas. Human studies have identified brain areas and transmitter systems involved in effort-based decision making and characterized the reduced selection of high-effort activities associated with motivational symptoms of depression and schizophrenia. Animal and human research on the neurochemistry of behavioral activation and effort-related processes makes an important conceptual contribution by illustrating the dissociable nature of distinct aspects of motivation.

Endoscopic implantation of autologous myoblasts for stress urinary incontinence and evaluation of its efficacy in sphincterotomized rabbits

INTRODUCTION

Stress urinary incontinence (SUI) is one of the health problems with more impact on patients' lives. The aim of the present work was to develop a therapy for SUI using tissue engineering by isolation and culture of autologous myoblasts (CAM) followed by endoscopic implantation. We also evaluated the efficacy of this therapy in a rabbit model of incontinence after sphincterotomy.

MATERIALS AND METHODS

We used healthy male New Zealand rabbits. The animals were first bled to obtain platelet-poor plasma (PPP) and biopsied for myoblast isolation. Post-sphincterotomy, they were divided into two groups: the treatment group (including animals that received CAM resuspended in PPP) and the control group (including animals receiving only PPP). The leak-point pressure (LPP) was used to measure continence in both groups at different time points. The results were evaluated with hierarchical linear regression models. Histological evaluation of the rabbits' sphincters was also performed at the end of follow-up.

RESULTS

No statistically significant differences were observed between the baseline LPP values of each group. The post-sphincterotomy values of both groups were below 50% of the baseline value, which was a mandatory condition for incontinence. The post-implantation values of the treatment group were higher than 50% of the baseline value, which led us to assume continence recovery. A statistically significant difference was observed in the LPP values between the two treatment groups (p=0.003). Histological study revealed interconnected islands formed by muscle fibers in the treatment group, and connective tissue surrounding the urethral lumen and inflammatory infiltrate in the control group.

DISCUSSION AND CONCLUSIONS

The implantation of CAM significantly improved LPP values in the treatment group, and the improvement remained throughout the evaluation period. It may be associated with the consistency of the implant and its stability at the injection site. Longer follow-up studies and human clinical investigations are required to consider CAM implantation as an alternative treatment for stress urinary incontinence.

Sex and age differences in mice models of effort-based decision-making and anergia in depression: the role of dopamine, and cerebral-dopamine-neurotrophic-factor

Mesolimbic dopamine (DA) regulates vigor in motivated behavior. While previous results have mainly been performed in male rodents, the present studies compared CD1 male and female mice in effort-based decision-making tests of motivation. These tests offered choices between several reinforcers that require different levels of effort (progressive ratio/choice task and 3-choice-T-maze task). Sweet reinforcers were used in both tasks. In the operant tasks, females worked harder as the task required more effort to access a 10% sucrose solution. Although males and females did not differ in preference for 10% vs 3% solutions under free concurrent presentation, females consumed more of the 10% solution when tested alone. The operant task requires a long period of training and changes in the DA system due to age can be mediating long-term changes in effort. Thus, age and sex factors were evaluated in the T-maze task, which requires only a short training period. Both sexes and ages were equally active when habituated to the running wheel (RW), but females consumed more sweet pellets than males, especially at an older age. Both sexes had a strong preference for the RW compared to more sedentary reinforcers in the 3-choice-T-maze test, but older animals spent less time running and ate more than the young ones. The DA-depleting agent tetrabenazine reduced time running in older mice but not in adolescents. Cerebral-dopamine-neurotrophic-factor was reduced in older mice of both sexes compared to adolescent mice. These results emphasize the importance of taking into account differences in sex and age when evaluating willingness to exert effort for specific reinforcers.

Effects of the dopamine depleting agent tetrabenazine in tests evaluating different components of depressive-like behavior in mice: sex-dependent response to antidepressant drugs with SERT and DAT blocker profiles

BACKGROUND

Depression is a disorder twice as common in women than in men. There are sex differences in the symptomatology and treatment response to this disorder. Impairments in behavioral activation (i.e. anergia, fatigue) are often seen in people with depression and are highly resistant to treatment. The role of mesolimbic dopamine (DA) in regulating behavioral activation has been extensively studied in male rodents, but little is known in female rodents.

OBJECTIVE

The present studies assessed potential sex differences in rodent paradigms used to study different components of depressive-like behavior, and in the treatment response to antidepressants with different mechanisms of action.

METHODS

Male and female CD1 mice received Tetrabenazine (TBZ), a VMAT-2 blocker that depletes DA and induces depressive symptoms in humans. Mice were tested on the Forced Swim Test, (FST), the Dark-Light box (DL), the elevated plus maze (EPM), Social Interaction (SI) test, and sucrose preference and consumption using the two bottles test. In addition, bupropion (a DA reuptake inhibitor) or fluoxetine (a serotonin reuptake inhibitor) were used to reverse TBZ-induced anergia.

RESULTS

In the FST, bupropion reversed TBZ effects in both sexes but fluoxetine was only effective in female mice. DA depletion did not affect other aspects of depression such as anxiety, sociability or sucrose consumption, and there was no interaction with bupropion on these parameters. In TBZ treated-females SERT-blockers may be effective at reversing anergia in aversive contexts (FST), and potentiating avoidance of anxiogenic stimuli.

CONCLUSIONS

Pro-dopaminergic antidepressants seem more efficacious at improving anergia in both sexes than SERT-blockers.

Incidence of myocarditis among patients recovered from COVID-19 infection identified using cardiac magnetic resonance imaging

Funding Acknowledgements

Type of funding sources: None.

Introduction

Coronavirus disease 2019 (COVID-19) has caused significant morbidity and mortality worldwide and has been associated with several cardiac complications including myocarditis. COVID-19 patients with myocardial injury have worse clinical outcomes than those without cardiac involvement. Hence, early detection of myocardial involvement in those who have recovered would be helpful in risk stratification of these patients. Locally, there has been no literature regarding cardiac involvement detected by cardiac magnetic resonance (CMR) imaging among COVID-19 patients. This study aims to report the incidence of patients who developed myocarditis among those who recovered from COVID-19 infection and who underwent CMR imaging in our institution.

Methodology

A single-center retrospective cohort study was performed in our institution. Consecutive patients from January 1, 2020, to December 31, 2021, who were initially referred for cardiac CMR examination due to cardiac symptoms and who met the following inclusion criteria 1) 19 years old and above; 2) with a history of a previously confirmed diagnosis of COVID-19 using reverse transcription-polymerase chain reaction (RT-PCR) swab test; 3) patients were considered recovered by the discharging criteria and 4) underwent CMR imaging for evaluation to rule out myocarditis in our institution. The primary outcome was determining the number of patients with positive and negative conventional MRI findings based on late gadolinium enhancement and edema.

Results

Fifty-four percent (54%) of patients had positive conventional MRI findings indicative of myocarditis (myocardial edema or late gadolinium presence). The most common co-morbid condition remains to be Hypertension (55%), followed by Diabetes Mellitus (17%). Dyspnea, palpitations and chest discomfort were the most commonly reported symptoms in 29 (54%), 24 (44%) and 21 (39%) patients, respectively. Twenty-nine patients (54%) were observed with increased T2 signal or positive LGE. Myocardial edema was found in 9 (31%) patients. Among them, 8 (57%) patients were observed with positive LGE. There was no significant difference of LV and RV systolic function among patients with positive and negative conventional CMR findings.

Conclusion

Myocarditis is one of the cardiovascular complications among patients who recovered from COVID-19, as demonstrated by our cardiac MRI study. Evaluation of the cardiac status of recovered COVID-19 patients needs to be closely monitored, and cardiac MRI may be a sensitive imaging tool to investigate any cardiac involvement further. This study provided local data on those with potential structural changes and cardiac complications aligned with the clinical history, which may be unique in our population after recovering from the disease. Further research with a larger sample size, risk factors, and the intervention to prevent disease progression may need more attention.

Evidence of sheep and abattoir environment as important reservoirs of multidrug resistant Salmonella and extended-spectrum beta-lactamase Escherichia coli

The increase in antimicrobial-resistant (AMR) foodborne pathogens, including E. coli and Salmonella in animals, humans, and the environment, is a growing public health concern. Among animals, cattle, pigs, and chicken are reservoirs of these pathogens worldwide. There is a knowledge gap on the prevalence and AMR of foodborne pathogens in small ruminants (i.e., sheep and goats). This study investigates the prevalence and antimicrobial resistance of extended-spectrum beta-lactamase (ESBL) E. coli and Salmonella from sheep and their abattoir environment in North Carolina. We conducted a year-round serial cross-sectional study and collected a total of 1128 samples from sheep (n = 780) and their abattoir environment (n = 348). Sheep samples consisted of feces, cecal contents, carcass swabs, and abattoir resting area feces. Environmental samples consisted of soil samples, lairage swab, animal feed, and drinking water for animals. We used CHROMAgar EEC with 4 μg/ml of Cefotaxime for isolating ESBL E. coli, and ESBL production was confirmed by double-disk diffusion test. Salmonella was isolated and confirmed using standard methods. All of the confirmed isolates were tested against a panel of 14 antimicrobials to elucidate susceptibility profiles. The prevalence of ESBL E. coli and Salmonella was significantly higher in environmental samples (47.7% and 65.5%) compared to the sheep samples (19.5% and 17.9%), respectively (P < 0.0001). We recovered 318 ESBL E. coli and 368 Salmonella isolates from sheep and environmental samples. More than 97% (310/318) of ESBL E. coli were multidrug-resistant (MDR; resistant to ≥3 classes of antimicrobials). Most Salmonella isolates (77.2%, 284/368) were pansusceptible, and 10.1% (37/368) were MDR. We identified a total of 24 different Salmonella serotypes by whole genome sequencing (WGS). The most common serotypes were Agona (19.8%), Typhimurium (16.2%), Cannstatt (13.2%), Reading (13.2%), and Anatum (9.6%). Prevalence and percent resistance of ESBL E. coli and Salmonella isolates varied significantly by season and sample type (P < 0.0001). The co-existence of ESBL E. coli in the same sample was associated with increased percent resistance of Salmonella to Ampicillin, Chloramphenicol, Sulfisoxazole, Streptomycin, and Tetracycline. We presumed that the abattoir environment might have played a great role in the persistence and dissemination of resistant bacteria to sheep as they arrive at the abattoir. In conclusion, our study reaffirms that sheep and their abattoir environment act as important reservoirs of AMR ESBL E. coli and MDR Salmonella in the U.S. Further studies are required to determine associated public health risks.

Impact of Fluoxetine on Behavioral Invigoration of Appetitive and Aversively Motivated Responses: Interaction With Dopamine Depletion

Impaired behavioral activation and effort-related motivational dysfunctions like fatigue and anergia are debilitating treatment-resistant symptoms of depression. Depressed people show a bias towards the selection of low effort activities. To determine if the broadly used antidepressant fluoxetine can improve behavioral activation and reverse dopamine (DA) depletion-induced anergia, male CD1 mice were evaluated for vigorous escape behaviors in an aversive context (forced swim test, FST), and also with an exercise preference choice task [running wheel (RW)-T-maze choice task]. In the FST, fluoxetine increased active behaviors (swimming, climbing) while reducing passive ones (immobility). However, fluoxetine was not effective at reducing anergia induced by the DA-depleting agent tetrabenazine, further decreasing vigorous climbing and increasing immobility. In the T-maze, fluoxetine alone produced the same pattern of effects as tetrabenazine. Moreover, fluoxetine did not reverse tetrabenazine-induced suppression of RW time but it reduced sucrose intake duration. This pattern of effects produced by fluoxetine in DA-depleted mice was dissimilar from devaluing food reinforcement by pre-feeding or making the food bitter since in both cases sucrose intake time was reduced but animals compensated by increasing time in the RW. Thus, fluoxetine improved escape in an aversive context but decreased relative preference for active reinforcement. Moreover, fluoxetine did not reverse the anergic effects of DA depletion. These results have implications for the use of fluoxetine for treating motivational symptoms such as anergia in depressed patients.

Impact of Caffeine on Ethanol-Induced Stimulation and Sensitization: Changes in ERK and DARPP-32 Phosphorylation in Nucleus Accumbens

BACKGROUND

Caffeine is frequently consumed with ethanol to reduce the impairing effects induced by ethanol, including psychomotor slowing or incoordination. Both drugs modulate dopamine (DA)-related markers in accumbens (Acb), and Acb DA is involved in voluntary locomotion and locomotor sensitization. The present study determined whether caffeine can affect locomotion induced by acute and repeated ethanol administration in adult male CD-1 mice.

METHODS

Acute administration of caffeine (7.5 to 30.0 mg/kg) was evaluated for its effects on acute ethanol-induced (1.5 to 3.5 g/kg) changes in open-field horizontal locomotion, supported rearing, and rearing not supported by the wall. DA receptor-dependent phosphorylation markers were assessed: extracellular signal-regulated kinase (pERK), and dopamine-and cAMP-regulated phosphoprotein Mr32kDa phosphorylated at threonine 75 site (pDARPP-32-Thr75) in Acb core and shell. Acutely administered caffeine was also evaluated in ethanol-sensitized (1.5 g/kg) mice.

RESULTS

Acute ethanol decreased both types of rearing. Caffeine increased supported rearing but did not block ethanol -induced decreases in rearing. Both substances increased horizontal locomotion in a biphasic manner, and caffeine potentiated ethanol-induced locomotion. Although ethanol administered repeatedly induced sensitization of locomotion and unsupported rearing, acute administration of caffeine to ethanol-sensitized mice in an ethanol-free state resulted in blunted stimulant effects compared with those seen in ethanol-naïve mice. Ethanol increased pERK immunoreactivity in both subregions of the Acb, but coadministration with caffeine blunted this increase. There were no effects on pDARPP-32(Thr75) immunoreactivity.

CONCLUSIONS

The present results demonstrated that, after the first administration, caffeine potentiated the stimulating actions of ethanol, but did not counteract its suppressant or ataxic effects. Moreover, our results show that caffeine has less activating effects in ethanol-sensitized animals.

Energizing effects of bupropion on effortful behaviors in mice under positive and negative test conditions: modulation of DARPP-32 phosphorylation patterns

Motivational symptoms such as anergia, fatigue, and reduced exertion of effort are seen in depressed people. To model this, nucleus accumbens (Nacb) dopamine (DA) depletions are used to induce a low-effort bias in rodents tested on effort-based decision-making. We evaluated the effect of the catecholamine uptake blocker bupropion on its own, and after administration of tetrabenazine (TBZ), which blocks vesicular storage, depletes DA, and induces depressive symptoms in humans. Male CD1 mice were tested on a 3-choice-T-maze task that assessed preference between a reinforcer involving voluntary physical activity (running wheel, RW) vs. sedentary activities (sweet food pellet intake or a neutral non-social odor). Mice also were tested on the forced swim test (FST), two anxiety-related measures (dark-light box (DL), and elevated plus maze (EPM)). Expression of phosphorylated DARPP-32 (Thr34 and Thr75) was evaluated by immunohistochemistry as a marker of DA-related signal transduction. Bupropion increased selection of RW activity on the T-maze. TBZ reduced time running, but increased time-consuming sucrose, indicating an induction of a low-effort bias, but not an effect on primary sucrose motivation. In the FST, bupropion reduced immobility, increasing swimming and climbing, and TBZ produced the opposite effects. Bupropion reversed the effects of TBZ on the T-maze and the FST, and also on pDARPP32-Thr34 expression in Nacb core. None of these manipulations affected anxiety-related parameters. Thus, bupropion improved active behaviors, which were negatively motivated in the FST, and active behaviors that were positively motivated in the T-maze task, which has implications for using catecholamine uptake inhibitors for treating anergia and fatigue-like symptoms.

Effects of caffeine on ethanol-elicited place preference, place aversion and ERK phosphorylation in CD-1 mice

BACKGROUND

Epidemiological studies indicate a rise in the combined consumption of caffeinated and alcoholic beverages, which can lead to increased risk of alcoholic-beverage overconsumption. However, the effects of the combination of caffeine and ethanol in animal models related to aspects of drug addiction are still underexplored.

AIMS

To characterize the pharmacological interaction between caffeine and ethanol and establish if caffeine can affect the ability of ethanol (2 g/kg) to elicit conditioned place preference and conditioned place aversion, we administered caffeine (3 or 15 mg/kg) to male CD-1 mice before saline or ethanol. Moreover, we determined if these doses of caffeine could affect ethanol (2 g/kg) elicited extracellular signal-regulated kinase phosphorylation in brain areas, nucleus accumbens, bed nucleus of stria terminalis, central nucleus of the amygdala, and basolateral amygdala, previously associated with this type of associative learning.

RESULTS

In the place-conditioning paradigm, caffeine did not have an effect on its own, whereas ethanol elicited significant conditioned-place preference and conditioned-place aversion. Caffeine (15 mg/kg) significantly prevented the acquisition of ethanol-elicited conditioned-place preference and, at both doses, also prevented the acquisition of ethanol-elicited conditioned-place aversion. Moreover, both doses of caffeine also prevented ethanol-elicited extracellular signal-regulated kinase phosphorylation expression in all brain areas examined.

CONCLUSIONS

The present data indicate a functional antagonistic action of caffeine and ethanol on associative learning and extracellular signal-regulated kinase phosphorylation after an acute interaction. These results could provide exciting grounds for further studies, also in a translational perspective, of their pharmacological interaction modulating other processes involved in drug consumption and addiction.

The non-selective adenosine antagonist theophylline reverses the effects of dopamine antagonism on tremor, motor activity and effort-based decision-making

Considerable evidence indicates that adenosine and dopamine systems interact in the regulation of basal ganglia function. Nonselective adenosine antagonists such as the methylxanthine caffeine as well as selective adenosine A_2A antagonists have been shown to produce antiparkinsonian and antidepressant effects in animal models. The present studies were conducted to assess if another methylxantine, theophylline, can reverse motor and motivational impairments induced by dopamine antagonism in rats. RESULTS: Theophylline (3.75-30.0 mg/kg, IP) reversed tremulous jaw movements (TJMs), catalepsy, and locomotor suppression induced by the dopamine D2 antagonist pimozide. It also reversed TJMs induced by the muscarinic receptor agonist pilocarpine, which is a well-known tremorogenic agent. Parallel studies assessed the ability of theophylline (5.0-20.0 mg/kg, IP) to reverse the changes in effort-related choice behavior induced by the dopamine D1 antagonist ecopipam (0.2 mg/kg, IP) and the D2 antagonist haloperidol (0.1 mg/kg, IP). Rats were tested on two different operant choice tasks which assess the tendency to work for a preferred reinforcer by lever pressing (for palatable pellets or a high 5% sucrose solution) vs. approaching and consuming a less preferred reinforcer (freely available lab chow or a less concentrated 0.3% sucrose solution). Theophylline restored food and sucrose-reinforced lever pressing in animals treated with the D2 antagonist. However, it was unable to reverse the effects of the D1 antagonist. Overall, the effects of theophylline resembled those previously reported for adenosine A_2A antagonists, and suggest that theophylline could be clinically useful for the treatment of motor and motivational symptoms in humans.

The dopamine depleting agent tetrabenazine alters effort-related decision making as assessed by mouse touchscreen procedures

RATIONALE

Effort-based decision-making tasks allow animals to choose between preferred reinforcers that require high effort to obtain vs. low-effort/low reward options. Mesolimbic dopamine (DA) and related neural systems regulate effort-based choice. Tetrabenazine (TBZ) is a vesicular monoamine transport type-2 inhibitor that blocks DA storage and depletes DA. In humans, TBZ induces motivational dysfunction and depression. TBZ has been shown reliably to induce a low-effort bias in rats, but there are fewer mouse studies.

OBJECTIVES

The present studies used touchscreen operant procedures (Bussey-Saksida chambers) to assess the effects of TBZ on effort-based choice in mice.

METHODS

C57BL6 mice were trained to press an elevated lit panel on the touchscreen on a fixed ratio 1 schedule reinforced by strawberry milkshake, vs. approaching and consuming a concurrently available but less preferred food pellets (Bio-serv).

RESULTS

TBZ (2.0-8.0 mg/kg IP) shifted choice, producing a dose-related decrease in panel pressing but an increase in pellet intake. In contrast, reinforcer devaluation by pre-feeding substantially decreased both panel pressing and pellet intake. In free-feeding choice tests, mice strongly preferred the milkshake vs. the pellets, and TBZ had no effect on milkshake intake or preference, indicating that the TBZ-induced low-effort bias was not due to changes in primary food motivation or preference. TBZ significantly decreased tissue levels of nucleus accumbens DA.

CONCLUSION

The DA depleting agent TBZ induced an effort-related motivational dysfunction in mice, which may have clinical relevance for assessing novel drug targets for their potential use as therapeutic agents in patients with motivation impairments.

A systematic review of the indirect and social costs studies in fragility fractures

Fragility fractures (FF) are the main clinical consequence of osteoporosis. FF lead to a loss in quality of life (QL), increased dependency and higher costs due to loss of productivity. Despite this, very few studies have been performed about the indirect or social costs of FF. The objective of this review was to systematically synthesize published evidence regarding indirect costs of FF. We conducted a systematic literature review of empirical studies published as peer review papers between 1998 and 2019. A total of 295 papers were found about costs and osteoporosis. After an iterative process, only 16 papers fit the criteria of selection. Despite the important consequences for QL, only seven studies have included research of the issue and only one about dependency. Treatments are cost-effective, but adherence is low. Multiple fractures, older age and low socioeconomic profile imply higher costs. Most studies are performed using the human capital methodology. The main two variables are loss of productivity and absenteeism. Most of the people included in the samples are out of the active population. Those studies that include a follow-up period vary in a range between 3 months and 2 years. Depending on sample and methodology, the indirect costs (IC) are between 2 and 50%. The direct costs associated with FF generally far outweigh the IC. There is a lack of studies about the effects of treatments and adherence and about the dependency system. The changing role of women in coming generations will increase indirect costs.

Evaluation of Factors That Influence Dose Variability of Marek's Disease Vaccines

Marek's disease (MD) vaccines are cell-associated and require special handling and care during administration. Vaccine dose is evaluated by plaque assay and is indicated as the number of plaque-forming units (PFUs) per dose. The objectives of this study were to evaluate the dose variability within each vial of MD vaccines and to assess those factors (from both manufacturing and handling and administration of the vaccine) that could affect vaccine dose variability. Three experiments were conducted. Experiment 1 was to evaluate dose variability in 36 MD vaccine vials and the effect of manufacturing factors on dose variability. Vaccines were titrated 10 times. Dose variability was measured as the coefficient of variability (CV) calculated as standard deviation divided by average PFU and multiplied by 100. Our results showed that all evaluated vaccines had levels of CV ranging from 10% to 34%. Variability existed regardless of manufacturer, vaccine serotype, and batch. Experiment 2 was conducted to evaluate the effect of infectivity rate (IR) on CV. IR was artificially reduced by adding noninfected chicken embryo fibroblast to the reconstituted vaccine before titration. Our results showed that decreased IR results in higher CV. Experiment 3 was to evaluate the handling and administration factors (time and mixing during administration) on CV. Our results showed that CV tends to increase with time and that this effect is more remarkable if vaccines were not mixed. Our study emphasizes the relevance of proper handling of MD vaccines and shows that dose variability can jeopardize the uniformity of vaccination in a flock and therefore the success of vaccination.

Preference for Exercise vs. More Sedentary Reinforcers: Validation of an Animal Model of Tetrabenazine-Induced Anergia

Physical activities can have intrinsic motivational or reinforcing properties. The choice to engage in voluntary physical activity is undertaken in relation to the selection of other alternatives, such as sedentary behaviors, drugs, or food intake. The mesolimbic dopamine (DA) system plays a critical role in behavioral activation or exertion of effort, and DA antagonism or depletion induces anergia in effort-based decision-making tasks. However, little is known about the neural mechanisms underlying the decision-making processes that establish preferences for sedentary vs. activity-based reinforcers. In the present work with male CD1 mice, we evaluated the effect of tetrabenazine (TBZ), a DA-depleting agent, on a three-choice T-maze task developed to assess preference between reinforcers with different behavioral activation requirements and sensory properties [i.e., a running wheel (RW) vs. sweet pellets or a neutral nonsocial odor]. We also studied the effects of TBZ on the forced swim test (FST), which measures climbing and swimming in a stressful setting, and on anxiety tests [dark-light (DL) box and elevated plus maze (EPM)]. In the three-choice task, TBZ reduced time running in the wheel but increased time spent consuming sucrose, thus indicating reduced activation but relatively intact sucrose reinforcement. The effect of TBZ was not mimicked by motivational manipulations that change the value of the reinforcers, such as making the RW aversive or harder to move, food-restricting the animals, inducing a binge-like eating pattern, or introducing social odors. In the FST, TBZ decreased time climbing (most active behavior) and increased immobility but did not affect anxiety in the DL or EPM. These results indicate that the three-choice T-maze task could be useful for assessing DA modulation of preferences for exercise based on activation and effort requirements, differentiating those effects from changes in preference produced by altering physical requirements, food restriction state, and stress during testing.

Evidence of higher intramyocellular fat among normal and overweight Indians with prediabetes

BACKGROUND

The rise in prevalence rates of Type 2 Diabetes among Indians is well recognized. The research focus has been primarily to understand the changes in insulin sensitivity and beta cell dysfunction among Indians with Type 2 Diabetes. However, no data are available on the role of peripheral tissue, in particular intramyocellular lipid (IMCL) content and its impact on glucose homeostasis among Indians with prediabetes.

METHODS

28 male subjects (20-40 year) were studied. 13 with prediabetes (BMI ranging from 25.4 ± 2.9 kg/m²) and 15 controls (BMI ranging from 24.6 ± 2.8 kg/m²) were recruited. Body composition by dual energy X-ray absorptiometry (DXA), insulin sensitivity, insulin secretion rates were derived using the minimal model of C-peptide secretion and kinetics rates and skeletal muscle strength of the lower limb (quadriceps) was assessed using Isokinetic dynamometry. From muscle biopsy samples of the vastus lateralis, IMCL fat content (Oil red O staining) was determined.

RESULTS

The prediabetes group were older compared to controls (P < 0.01), but had similar BMI. The muscle to fat ratio, plasma Insulin, C peptide, HOMA-IR and HOMA % B were also comparable between the groups. IMCL fat content (%) was significantly higher in the prediabetes group compared to controls (7.0 ± 0.7% vs. 2.0 ± 0.3%, P < 0.01). This difference persisted even after controlling for age. Overall the IMCL fat content (%) was positively and significantly associated with HbA1c (r = 0.76, P < 0.01). HOMA-IR was significantly correlated with central (android, trunk) adiposity (kg) (r = 0.71, P < 0.01) but not with IMCL (%).

CONCLUSIONS

This is the first direct evidence of existence of significantly higher lipid levels within skeletal muscle cells among normal and overweight young Indians with prediabetes. However, there was no association between IMCL and HOMA-IR among the prediabetes group.

The Psychopharmacology of Effort-Related Decision Making: Dopamine, Adenosine, and Insights into the Neurochemistry of Motivation

Effort-based decision making is studied using tasks that offer choices between high-effort options leading to more highly valued reinforcers versus low-effort/low-reward options. These tasks have been used to study the involvement of neural systems, including mesolimbic dopamine and related circuits, in effort-related aspects of motivation. Moreover, such tasks are useful as animal models of some of the motivational symptoms that are seen in people with depression, schizophrenia, Parkinson's disease, and other disorders. The present review will discuss the pharmacology of effort-related decision making and will focus on the use of these tasks for the development of drug treatments for motivational dysfunction. Research has identified pharmacological conditions that can alter effort-based choice and serve as models for depression-related symptoms (e.g., the vesicular monoamine transport-2 inhibitor tetrabenazine and proinflammatory cytokines). Furthermore, tests of effort-based choice have identified compounds that are particularly useful for stimulating high-effort work output and reversing the deficits induced by tetrabenazine and cytokines. These studies indicate that drugs that act by facilitating dopamine transmission, as well as adenosine A_2A antagonists, are relatively effective at reversing effort-related impairments. Studies of effort-based choice may lead to the identification of drug targets that could be useful for treating motivational treatments that are resistant to commonly used antidepressants such as serotonin transport inhibitors.

Demotivating outcome of asymmetrical Nucleus Accumbens disconnection for cocaine related disorder: a translational point of view

Letter to the editor.

Stillbirth rates in 20 countries of Latin America: an ecological study

OBJECTIVE

To describe country-level stillbirth rates and their change over time in Latin America, and to measure the association of stillbirth rates with socio-economic and health coverage indicators in the region.

DESIGN

Ecological study.

SETTING

20 countries of Latin America.

POPULATION OR SAMPLE

Aggregated data from pregnant women with countries as units of analysis.

METHODS

We used stillbirth estimates, and socio-economic and healthcare coverage indicators reported from 2006 to 2016 from UNICEF, United Nations Development Programme and World Bank datasets. We calculated Spearman's correlation coefficients between stillbirths rates and socioeconomic and health coverage indicators.

MAIN OUTCOME MEASURES

National estimates of stillbirth rates in each country.

RESULTS

The estimated stillbirth rate for Latin America for 2015 was 8.1 per 1000 births (range 3.1-24.9). Seven Latin America countries had rates higher than 10 stillbirths per 1000 births. The average annual reduction rate for the region was 2% (range 0.1-3.8%), with the majority of Latin America countries ranging between 1.5 and 2.5%. National stillbirth rates were correlated to: women's schooling (rS = -0.7910), gross domestic product per capita (rS = -0.8226), fertility rate (rS = 0.6055), urban population (rS = -0.6316), and deliveries at health facilities (rS = -0.6454).

CONCLUSIONS

Country-level estimated stillbirth rates in Latin America varied widely in 2015. The trend and magnitude of reduction in stillbirth rates between 2000 and 2015 was similar to the world average. Socio-economic and health coverage indicators were correlated to stillbirth rates in Latin America.

TWEETABLE ABSTRACT

Stillbirth rates decreased in Latin America but remain relatively high, with wide variations among countries.

Dopamine depletion shifts behavior from activity based reinforcers to more sedentary ones and adenosine receptor antagonism reverses that shift: Relation to ventral striatum DARPP32 phosphorylation patterns

The mesolimbic dopamine (DA) system plays a critical role in behavioral activation and effort-based decision-making. DA depletion produces anergia (shifts to low effort options) in animals tested on effort-based decision-making tasks. Caffeine, the most consumed stimulant in the world, acts as an adenosine A₁/A_2A receptor antagonist, and in striatal areas DA D₁ and D₂ receptors are co-localized with adenosine A₁ and A_2A receptors respectively. In the present work, we evaluated the effect of caffeine on anergia induced by the VMAT-2 inhibitor tetrabenazine (TBZ), which depletes DA. Anergia was evaluated in a three-chamber T-maze task in which animals can chose between running on a wheel (RW) vs. sedentary activities such as consuming sucrose or sniffing a neutral odor. TBZ-caffeine interactions in ventral striatum were evaluated using DARPP-32 phosphorylation patterns as an intracellular marker of DA-adenosine receptor interaction. In the T-maze, control mice spent more time running and much less consuming sucrose or sniffing. TBZ (4.0 mg/kg) reduced ventral striatal DA tissue levels as measured by HPLC, and also shifted preferences in the T-maze, reducing selection of the reinforcer that involved vigorous activity (RW), but increasing consumption of a reinforcer that required little effort (sucrose), at doses that had no effect on independent measures of appetite or locomotion in a RW. Caffeine at doses that had no effect on their own reversed the effects of TBZ on T-maze performance, and also suppressed TBZ-induced pDARPP-32(Thr34) expression as measured by western blot, suggesting a role for D₂-A_2A interactions. These results support the idea that DA depletion produces anergia, but does not affect the primary motivational effects of sucrose. Caffeine, possibly by acting on A_2A receptors in ventral striatum, reversed the DA depletion effects. It is possible that caffeine, like selective adenosine A2A antagonists, could have some therapeutic benefit for treating effort-related symptoms.

Caffeine and Selective Adenosine Receptor Antagonists as New Therapeutic Tools for the Motivational Symptoms of Depression

Major depressive disorder is one of the most common and debilitating psychiatric disorders. Some of the motivational symptoms of depression, such anergia (lack of self-reported energy) and fatigue are relatively resistant to traditional treatments such as serotonin uptake inhibitors. Thus, new pharmacological targets are being investigated. Epidemiological data suggest that caffeine consumption can have an impact on aspects of depressive symptomatology. Caffeine is a non-selective adenosine antagonist for A1/A2A receptors, and has been demonstrated to modulate behavior in classical animal models of depression. Moreover, selective adenosine receptor antagonists are being assessed for their antidepressant effects in animal studies. This review focuses on how caffeine and selective adenosine antagonists can improve different aspects of depression in humans, as well as in animal models. The effects on motivational symptoms of depression such as anergia, fatigue, and psychomotor slowing receive particular attention. Thus, the ability of adenosine receptor antagonists to reverse the anergia induced by dopamine antagonism or depletion is of special interest. In conclusion, although further studies are needed, it appears that caffeine and selective adenosine receptor antagonists could be therapeutic agents for the treatment of motivational dysfunction in depression.

Individual differences in the energizing effects of caffeine on effort-based decision-making tests in rats

Motivated behavior is characterized by activation and high work output. Nucleus accumbens (Nacb) modulates behavioral activation and effort-based decision-making. Caffeine is widely consumed because of its energizing properties. This methylxanthine is a non-selective adenosine A₁/A_2A receptor antagonist. Adenosine receptors are highly concentrated in Nacb. Adenosine agonists injected into Nacb, shift preference towards low effort alternatives. The present studies characterized effort-related effects of caffeine in a concurrent progressive ratio (PROG)/free reinforcer choice procedure that requires high levels of work output, and generates great variability among different animals. Male Sprague-Dawley rats received an acute dose of caffeine (2.5-20.0 mg/kg, IP) and 30 min later were tested in operant boxes. One group was food-restricted and had to lever pressed for high carbohydrate pellets, another group was non-food-restricted and lever pressed for a high sucrose solution. Caffeine (2.5 and 5.0 mg/kg) increased lever pressing in food-restricted animals that were already high responders. However, in non-restricted animals, caffeine (5.0 and 10.0 mg/kg) increased work output only among low responders. In fact, caffeine (10.0 and 20.0 mg/kg) in non-restricted animals, reduced lever pressing among high responders in the PROG task, and also in a different group of animals lever pressing in an easy task (fixed ratio 7 schedule) that uniformly generates high levels of responding. Caffeine did not modify sucrose preference or consumption under free access conditions. Thus, when animals do not have a homeostatic need, caffeine can help those not very intrinsically motivated to work harder for a more palatable reward. However, caffeine can disrupt performance of animals intrinsically motivated to work hard for a better reward.

Caffeine Modulates Food Intake Depending on the Context That Gives Access to Food: Comparison With Dopamine Depletion

Caffeine is a methylxanthine consumed in different contexts to potentiate alertness and reduce fatigue. However, caffeine can induce anxiety at high doses. Caffeine is also a minor psychostimulant that seems to act as an appetite suppressant, but there are also reports indicating that it could stimulate appetite. Dopamine also is involved in food motivation and in behavioral activation. In the present series of experiments, we evaluated the effects of acute administration of caffeine on food consumption under different access conditions. CD1 male adult mice had access to highly palatable food (50% sucrose) in a restricted but habitual context, under continuous or intermittent access as well as under anxiogenic, or effortful conditions. Caffeine (2.5-20.0 mg/kg) increased intake at the highest dose under familiar continuous and intermittent access. However, this high dose reduced food intake in the dark-light paradigm. In contrast, a dopamine-depleting agent, tetrabenazine (TBZ; 1.0-8.0 mg/kg) did not affect food intake in any of those experimental conditions. In the T-maze-barrier task that evaluates seeking and taking of food under effortful conditions, caffeine (10.0 mg/kg) decreased latency to reach the food, but did not affect selection of the high-food density arm that required more effort, or the total amount of food consumed. In contrast, TBZ (4.0 mg/kg) reduced selection of the high food density arm with the barrier, thus affecting amount of food consumed. Interestingly, a small dose of caffeine (5.0 mg/kg) was able to reverse the anergia-inducing effects produced by TBZ in the T-maze. These results suggest that caffeine can potentiate or suppress food consumption depending on the context. Moreover, caffeine did not change appetite, and did not impair orientation toward food under effortful conditions, but it rather helped to achieve the goal by improving speed and by reversing performance to normal levels when fatigue was induced by dopamine depletion.

Bartonella Seroepidemiology in Dogs from North America, 2008-2014

BACKGROUND

Improved understanding of Bartonella species seroepidemiology in dogs may aid clinical decision making and enhance current understanding of naturally occurring arthropod vector transmission of this pathogen.

OBJECTIVES

To identify demographic groups in which Bartonella exposure may be more likely, describe spatiotemporal variations in Bartonella seroreactivity, and examine co-exposures to other canine vector-borne diseases (CVBD).

ANIMALS

A total of 15,451 serology specimens from dogs in North America were submitted to the North Carolina State University, College of Veterinary Medicine Vector Borne Disease Diagnostic Laboratory between January 1, 2008, and December 31, 2014.

METHODS

Bartonella henselae, Bartonella koehlerae, and Bartonella vinsonii subspecies berkhoffii indirect fluorescent antibody (IFA) serology results, as well as results from a commercial assay kit screening for Dirofilaria immitis antigen and Ehrlichia species, Anaplasma phagocytophilum, and Borrelia burgdorferi antibodies, and Ehrlichia canis, Babesia canis, Babesia gibsoni, and Rickettsia species IFA results were reviewed retrospectively.

RESULTS

Overall, 3.26% of dogs were Bartonella spp. seroreactive; B. henselae (2.13%) and B. koehlerae (2.39%) were detected more frequently than B. vinsonii subsp. berkhoffii (1.42%, P < 0.0001). Intact males had higher seroreactivity (5.04%) than neutered males (2.87%, P < 0.0001) or intact or spayed females (3.22%, P = 0.0003). Mixed breed dogs had higher seroreactivity (4.45%) than purebred dogs (3.02%, P = 0.0002). There was no trend in seasonal seroreactivity; geographic patterns supported broad distribution of exposure, and co-exposure with other CVBD was common.

CONCLUSIONS AND CLINICAL IMPORTANCE

Bartonella spp. exposure was documented throughout North America and at any time of year. Male intact dogs, mixed breed dogs, and dogs exposed to other CVBD have higher seroreactivity to multiple Bartonella species.

Taxonomía y ecología del orden <i>Trichoptera</i> en el departamento de Antioquia en diferentes pisos altitudinales

De febrero de 1978 a agosto de 1979 se llevó a cabo el estudio ecológico y taxonómico del orden Trichoptera en el Departamento de Antioquia a diferentes pisos altitudinales. En total se estudiaron 18 estaciones ecosistemas acuáticos lóticos, correspondientes a cinco pisos altitudinales, de 500 m. a 2.800 m. de altura. Se hicieron mediciones fisicoquímicas como 02,CO2, pH, conductividad, temperatura del agua, nitratos y fosfatos. Se observó un incremento de 02 y una disminución de los valores de CO2, pH y conductividad con la altura.Además, se hizo un inventario de la fauna béntica en general y se sacaron valores de índice de diversidad por piso altitudinal para dichos organismos, observándose por ejempló, como algunos grupos taxonómicos tienden a disminuir con la altura.El estudio taxonómico y ecológico se centró en las larvas de los tricópteros encontrándose un total de 12 familias, 20 géneros y 3 especies reconfirmadas. De los cuales el género Mortoniella fue el más abundante y Wormaldia, Xiphocentron y Ochrotrichia los de más bajo porcentaje. Los géneros de mayor distribución en los diferentes pisos altitudinales fueron Leptomena y Smicridea. Se reportó por primera vez para el neotrópico Grumichella, Triplectides y Mortoniella. Se observó además, como a mayor altura se presentaba una mayor diversidad de los tricópteros.

Retrospective analysis of jaw biopsies in young adults. A study of 1599 cases in Southern Brazil

BACKGROUND

To evaluate the prevalence and the characteristics of jaw lesions diagnosed in young adults aged 20 to 30 years in a southern Brazil reference center, over a period of 25 years. And to analyze the concordance between clinical and histological diagnosis.

MATERIAL AND METHODS

In this cross-sectional retrospective study, the biopsies files from this center were retrieved and data regarding sex, age, bone localization, clinical and histological diagnosis were collected. The histological diagnosis were grouped into the categories Cystic lesions of odontogenic origin, Periapical inflammation, Odontogenic tumors, Bone diseases, Health tissue and Nonspecific diagnostic. Absolute and relative frequencies were estimated with descriptive analysis. The agreement between clinical and histological diagnosis was measured through Kappa statistic.

RESULTS

A total of 18,181 histopathological analysis were performed during the period of the study, registering 1,599 jaw lesions in young adults. The average age of individuals was 24,59 years (SD 3,1). Nine hundred ninety-one (62%) lesions were found in females and 608 (38%) in males. More than half of pathologies were cystic lesions of odontogenic origin (822/51.4%), followed by periapical inflammation (282/17.6%). Regarding the site of lesions, more than half occurred in posterior mandible (877/54.8%), followed by posterior maxilla (339/21.2%). The most frequent entities were periapical cyst, chronic periapical granuloma, dental follicle and paradental cyst, corresponding to a total of 1,202 (75.2%) evaluated cases. In relation to the analysis of concordance between clinical and histological diagnosis the general Kappa index was 0.5, which is considered moderate. Finally, the findings confirm data from literature about the most frequent jaw pathologies in young adults and serve as aid for preventive measures of some entities. Additionally, they can improve the formulation of differential diagnosis and the patient management.

Association between Gallbladder Ultrasound Findings and Bacterial Culture of Bile in 70 Cats and 202 Dogs

Background

Bacterial cholecystitis often is diagnosed by combination of gallbladder ultrasound (US) findings and positive results of bile culture. The value of gallbladder US in determining the likelihood of bile bacterial infection in cats and dogs with suspected biliary disease is unknown.

Hypothesis/Objectives

To determine the value of gallbladder US in predicting bile bacterial culture results, identify most common bacterial isolates from bile, and describe complications after cholecystocentesis in cats and dogs with suspected hepatobiliary disease.

Animals

Cats (70) and dogs (202) that underwent an abdominal US and submission of bile for culture were included in the study.

Methods

A cross‐sectional study design was used to determine the association of gallbladder US abnormalities and the results of bile cultures, and complications of cholecystocentesis.

Results

Abnormal gallbladder US had high sensitivity (96%) but low specificity (49%) in cats with positive and negative results of bile bacterial culture, respectively. Cats with normal gallbladder US findings were unlikely to have positive bile bacterial culture (negative predictive value of 96%). Gallbladder US had lower sensitivity (81%), specificity (31%), positive predictive value (20%), and negative predictive value (88%) in dogs. The most common bacterial isolates were of enteric origin, the prevalence being higher in cats. Incidence of complications after cholecystocentesis was 3.4%.

Conclusions and clinical importance

Gallbladder US has a high negative predictive value for bile culture results in cats. This modality is less predictive of infection in dogs. Percutaneous US‐guided cholecystocentesis has a low complication rate.

Genetic diversity of armored scales (Hemiptera: Diaspididae) and soft scales (Hemiptera: Coccidae) in Chile

Scale insects (Sternorrhyncha: Coccoidea) are one of the most invasive and agriculturally damaging insect groups. Their management and the development of new control methods are currently jeopardized by the scarcity of identification data, in particular in regions where no large survey coupling morphological and DNA analyses have been performed. In this study, we sampled 116 populations of armored scales (Hemiptera: Diaspididae) and 112 populations of soft scales (Hemiptera: Coccidae) in Chile, over a latitudinal gradient ranging from 18°S to 41°S, on fruit crops, ornamental plants and trees. We sequenced the COI and 28S genes in each population. In total, 19 Diaspididae species and 11 Coccidae species were identified morphologically. From the 63 COI haplotypes and the 54 28S haplotypes uncovered, and using several DNA data analysis methods (Automatic Barcode Gap Discovery, K2P distance, NJ trees), up to 36 genetic clusters were detected. Morphological and DNA data were congruent, except for three species (Aspidiotus nerii, Hemiberlesia rapax and Coccus hesperidum) in which DNA data revealed highly differentiated lineages. More than 50% of the haplotypes obtained had no high-scoring matches with any of the sequences in the GenBank database. This study provides 63 COI and 54 28S barcode sequences for the identification of Coccoidea from Chile.

Abstract P4-07-10: Epithelial mesenchymal transition associated with high miR-221 and integrin β6 leads to poor prognosis in hormone receptor positive HER2 negative breast cancers

Background: MicroRNA mediated molecular alterations are involved in the initiation and progression of cancer. Altered expression of multiple microRNAs is associated with endocrine resistance in hormone receptor positive HER2 negative (HR+/HER2-ve) cancer. The role of miR-221 in inducing epithelial to mesenchymal transition (EMT) is well documented especially in cell line model systems. However, the detailed mechanism of specific microRNAs in intrinsic and acquired resistance to endocrine therapy needs to be worked out. In addition, more needs to be done in the documentation of these mechanisms in human breast cancer specimens with complete clinical documentation and long-term follow-up. In this study, we have evaluated the clinical significance of miR-221 and its mechanistic role in EMT using human specimens and cell line models.

Materials and Methods: Formalin fixed paraffin embedded tumor from 129 HR+/HER2-ve breast cancer patients with a median follow up of 63 months were used for estimation of miR-221 by quantitative real time PCR. Expression levels of genes which are direct targets of miR-221 and related genes in EMT were analysed from these tumors. Survival between miR-221 high and low groups was compared by Kaplan Meier survival curves and prognostic relevance was estimated by Cox proportional hazard model.

Cell line experiments to investigate the role of miR-221 in inducing EMT through integrin β6 are underway in both wild type and tamoxifen resistant MCF-7 cell lines (A gift from Prof Ben Ho Park, Johns Hopkins University School of Medicine).

Results: A significant elevated level of miR-221 was observed in small proportion (14%) of HR+/HER2-ve tumors. miR-221 expression had an inverse correlation with both ER protein and ESR1 mRNA levels within HR+/HER2-ve tumors. Tumors with high levels of miR-221 showed significantly higher expression of integrin β6 which is a robust marker of EMT. Patients with high expression of miR-221 had a poorer survival in Kaplan Meier analysis.

Results of interrogation of EMT mediated through integrin related pathways involving miR-221 in cell line models will be presented.

Discussion: The association between miR-221 and integrin β6 in HR+/HER2-ve breast cancer with endocrine resistance suggests a potential link between an epigenetic regulator and a mediator of tumor-stromal interaction. The other mediators involved in this pathway are being investigated. miR-221 could be potentially used as a marker for identification of a poor prognostic subtype within HR+/HER2-ve breast cancers.

Citation Format: Prabhu JS, Kaul R, Korlimarla A, Desai K, Gangadharan C, Rajarajan S, Nair MG, Alexander A, Kaluve R, Manjunath S, Correa M, Prasad MSN, Patil S, Srinath BS, Sridhar TS. Epithelial mesenchymal transition associated with high miR-221 and integrin β6 leads to poor prognosis in hormone receptor positive HER2 negative breast cancers [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-07-10.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

Effort-related motivational effects of the pro-inflammatory cytokine interleukin-6: pharmacological and neurochemical characterization

RATIONALE

Motivational dysfunctions such as anergia, fatigue, and reduced effort expenditure are common in patients with depression and other disorders. Pro-inflammatory cytokines are implicated in depression, and cytokine administration induces motivational deficits in humans.

OBJECTIVES

These studies focused on the effects of the cytokine interleukin-6 (IL-6) on effort-related decision-making.

METHODS

Rats were assessed using the concurrent fixed ratio 5-lever pressing/chow feeding choice procedure, which measures the tendency of rats to work for a preferred food (high carbohydrate pellets) in the presence of a concurrently available but less preferred substitute (lab chow).

RESULTS

IL-6 (2.0-8.0 μg/kg IP) shifted choice behavior, significantly decreasing lever pressing and increasing chow intake. Further experiments showed that the adenosine A2A antagonist MSX-3 and the stimulant methylphenidate attenuated the effort-related impairments produced by IL-6, increasing lever pressing and decreasing chow intake in IL-6 treated rats. The same doses of IL-6 did not alter food intake or preference in parallel free-feeding choice studies, demonstrating that these low doses were not altering preference for the high carbohydrate pellets or generally suppressing appetite. Also, IL-6 did not affect body temperature. Microdialysis studies showed that 8.0 μg/kg IL-6 significantly decreased extracellular dopamine in nucleus accumbens core.

CONCLUSIONS

In summary, IL-6 reduces the tendency to work for food, even at low doses that do not produce fever or loss of appetite. Dopaminergic mechanisms may be involved in these effort-related effects. This research has implications for the involvement of cytokines in motivational dysfunctions such as anergia and fatigue.

Activational and effort-related aspects of motivation: neural mechanisms and implications for psychopathology

Motivation has been defined as the process that allows organisms to regulate their internal and external environment, and control the probability, proximity and availability of stimuli. As such, motivation is a complex process that is critical for survival, which involves multiple behavioural functions mediated by a number of interacting neural circuits. Classical theories of motivation suggest that there are both directional and activational aspects of motivation, and activational aspects (i.e. speed and vigour of both the instigation and persistence of behaviour) are critical for enabling organisms to overcome work-related obstacles or constraints that separate them from significant stimuli. The present review discusses the role of brain dopamine and related circuits in behavioural activation, exertion of effort in instrumental behaviour, and effort-related decision-making, based upon both animal and human studies. Impairments in behavioural activation and effort-related aspects of motivation are associated with psychiatric symptoms such as anergia, fatigue, lassitude and psychomotor retardation, which cross multiple pathologies, including depression, schizophrenia, and Parkinson's disease. Therefore, this review also attempts to provide an interdisciplinary approach that integrates findings from basic behavioural neuroscience, behavioural economics, clinical neuropsychology, psychiatry, and neurology, to provide a coherent framework for future research and theory in this critical field. Although dopamine systems are a critical part of the brain circuitry regulating behavioural activation, exertion of effort, and effort-related decision-making, mesolimbic dopamine is only one part of a distributed circuitry that includes multiple neurotransmitters and brain areas. Overall, there is a striking similarity between the brain areas involved in behavioural activation and effort-related processes in rodents and in humans. Animal models of effort-related decision-making are highly translatable to humans, and an emerging body of evidence indicates that alterations in effort-based decision-making are evident in several psychiatric and neurological disorders. People with major depression, schizophrenia, and Parkinson's disease show evidence of decision-making biases towards a lower exertion of effort. Translational studies linking research with animal models, human volunteers, and clinical populations are greatly expanding our knowledge about the neural basis of effort-related motivational dysfunction, and it is hoped that this research will ultimately lead to improved treatment for motivational and psychomotor symptoms in psychiatry and neurology.

Choosing voluntary exercise over sucrose consumption depends upon dopamine transmission: effects of haloperidol in wild type and adenosine A₂AKO mice

RATIONALE

Mesolimbic dopamine (DA) regulates behavioral activation and effort-related decision-making in motivated behaviors. Mesolimbic DA D2 receptors are co-localized with adenosine A2A receptors, and they interact in an antagonistic manner.

OBJECTIVES

A T-maze task was developed to assess dopaminergic involvement in preference between a reinforcer that involves vigorous voluntary activity (running wheel) and a reinforcer that requires minimal behavioral activation (sucrose pellets). Haloperidol (D2 antagonist) was administered to adenosine A2A receptor knockout (A2AKO) and wild-type (WT) littermate controls to assess the involvement of these two receptors in the selection of running wheel activity versus sucrose consumption.

RESULTS

Under control conditions, mice spent more time running and less time eating. In WT mice, haloperidol reduced time running but actually increased time-consuming sucrose. However, A2AKO mice did not show the haloperidol-induced shift from running wheel activity to sucrose intake. Prefeeding reduced sucrose consumption in the T-maze in both strains, indicating that this paradigm is sensitive to motivational devaluation. Haloperidol increased c-Fos immunoreactivity in anterior cingulate cortex (ACg) and nucleus accumbens (Acb) core of WT but not KO mice.

CONCLUSIONS

These results indicate that after DA antagonism, the preference for vigorous physical activity is reduced, while palatable food selection increases. Adenosine A2A receptor deletion provides resistance to these effects of D2 receptor antagonism. These two receptors in Acb core and ACg seem to be involved in the regulation of the intrinsic reinforcing characteristics of voluntary exercise but not in the regulation of the primary reinforcing characteristics of palatable sedentary reinforcers.

Phytochemical, antioxidant and anticancer activities of extracts of seven fruits found in the Southern Brazilian flora

Methanol extracts of seven edible fruits found in southern Brazil: Garcinia achachairu, Rubus imperialis, Rubus rosaefolius, Solanum quitoense, Solanum sessiliflorun, Diospyros inconstans and Plinia glomerata, were evaluated for their total phenol content and antioxidant activity in different in vitro free radical scavenging models. In addition, studies were performed on cell viability of extracts of the seeds of G. achachairu against murine melanoma cells. The fruits peel and seeds of G. achachairu were very promising in terms of total phenol content (data in gallic acid equivalent per gram), as assessed by the Folin-Ciocalteu method, with values of 9.70±3.2 and 8.40±1.1, respectively. On the other hand, antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl scavenging assay showed that the fruit pulp and peel of P. glomerata presented the best profile, with values of the 16.3±1.8 and 15.9±2.4 μg/ml, respectively. Regarding the cytotoxic effect of methanol extract and guttiferone A from G. achachairu, we have observed that both inhibit the growth of B16F10 tumor cells, with calculated IC₅₀ values of 49.6±2.1 mg/ml and 48.6±5.4 mM, respectively.

Neurobiological basis of motivational deficits in psychopathology

In recent years, there has been increasing emphasis on the importance of motivational symptoms in depression, schizophrenia and other disorders. The present review discusses the conceptual background related to the construct of motivation, and provides a framework that for research on both physiological and pathological aspects of motivation. Particular emphasis is placed on what is known about the neurobiological basis of activational aspects of motivation, including studies from animal models. The role of limbic/prefrontal/striatal circuitry in behavioral activation and effort-related functions is examined, and the utility of behavioral tasks of effort-based decision making as models of motivational symptoms is discussed. We also review the neurobiology of motivational symptoms in relation to psychopathology, and issues related to the language used to characterize motivational dysfunctions are considered. The literature suggests that research on the neurobiology of motivational dysfunction in psychopathology, at both clinical and preclinical levels, could inform the development of novel and more effective treatments for a range of CNS disorders.