Alcohol is a major contributor to global disease and a leading cause of preventable death, causing approximately 88,000 deaths annually in the United States alone. Alcohol use disorder is one of the ...most common psychiatric disorders, with nearly one-third of U.S. adults experiencing alcohol use disorder at some point during their lives. Alcohol use disorder also has economic consequences, costing the United States at least $249 billion annually. Current pharmaceutical and behavioral treatments may assist patients in reducing alcohol use or facilitating alcohol abstinence. Although recent research has expanded understanding of alcohol use disorder, more research is needed to identify the neurobiological, genetic and epigenetic, psychological, social, and environmental factors most critical in the etiology and treatment of this disease. Implementation of this knowledge in clinical practice and training of health care providers is also needed to ensure appropriate diagnosis and treatment of individuals suffering from alcohol use disorder.
Oxytocin (OT) is a potential treatment for multiple neuropsychiatric disorders. As OT is a peptide, delivery by the intranasal (IN) route is the preferred method in clinical studies. Although studies ...have shown increased cerebrospinal fluid (CSF) OT levels following IN administration, this does not unequivocably demonstrate that the peripherally administered OT is entering the CSF. For example, it has been suggested that peripheral delivery of OT could lead to central release of endogenous OT. It is also unknown whether the IN route provides for more efficient entry of the peptide into the CSF compared to the intravenous (IV) route, which requires blood-brain barrier penetration. To address these questions, we developed a sensitive and specific quantitative mass spectrometry assay that distinguishes labeled (d5-deuterated) from endogenous (d0) OT. We administered d5 OT (80 IU) to six nonhuman primates via IN and IV routes as well as IN saline as a control condition. We measured plasma and CSF concentrations of administered and endogenous OT before (t=0) and after (t=10, 20, 30, 45 and 60 min) d5 OT dosing. We demonstrate CSF penetrance of d5, exogenous OT delivered by IN and IV administration. Peripheral administration of d5 OT did not lead to increased d0, endogenous OT in the CSF. This suggests that peripheral administration of OT does not lead to central release of endogenous OT. We also did not find that IN administration offered an advantage compared to IV administration with respect to achieving greater CSF concentrations of OT.
Abstract
Oxytocin may have promise as a treatment for neuropsychiatric disorders. Its therapeutic effect may depend on its ability to enter the brain and bind to the oxytocin receptor. To date, the ...brain tissue penetrance of intranasal oxytocin has not been demonstrated. In this nonhuman primate study, we administer deuterated oxytocin intranasally and intravenously to rhesus macaques and measure, with mass spectrometry, concentrations of labeled (exogenously administered) and endogenous oxytocin in 12 brain regions two hours after oxytocin administration. Labeled oxytocin is quantified after intranasal (not intravenous) administration in brain regions (orbitofrontal cortex, striatum, brainstem, and thalamus) that lie in the trajectories of the olfactory and trigeminal nerves. These results suggest that intranasal administration bypasses the blood–brain barrier, delivering oxytocin to specific brain regions, such as the striatum, where oxytocin acts to impact motivated behaviors. Further, high concentrations of endogenous oxytocin are in regions that overlap with projection fields of oxytocinergic neurons.
Lytic polysaccharide monooxygenases (LPMOs) are industrially important copper-dependent enzymes that oxidatively cleave polysaccharides. Here we present a functional and structural characterization ...of two closely related AA9-family LPMOs from Lentinus similis (LsAA9A) and Collariella virescens (CvAA9A). LsAA9A and CvAA9A cleave a range of polysaccharides, including cellulose, xyloglucan, mixed-linkage glucan and glucomannan. LsAA9A additionally cleaves isolated xylan substrates. The structures of CvAA9A and of LsAA9A bound to cellulosic and non-cellulosic oligosaccharides provide insight into the molecular determinants of their specificity. Spectroscopic measurements reveal differences in copper co-ordination upon the binding of xylan and glucans. LsAA9A activity is less sensitive to the reducing agent potential when cleaving xylan, suggesting that distinct catalytic mechanisms exist for xylan and glucan cleavage. Overall, these data show that AA9 LPMOs can display different apparent substrate specificities dependent upon both productive protein-carbohydrate interactions across a binding surface and also electronic considerations at the copper active site.
Ghrelin, a stomach-derived hormone implicated in numerous behaviors including feeding, reward, stress, and addictive behaviors, acts by binding to the growth hormone secretagogue receptor (GHSR). ...Here, we present the development, verification, and initial characterization of a novel GHSR knockout (KO) Wistar rat model created with CRISPR genome editing.
Using CRISPR/Cas9, we developed a GHSR KO in a Wistar background. Loss of GHSR mRNA expression was histologically verified using RNAscope in wild-type (WT; n = 2) and KO (n = 2) rats. We tested the effects of intraperitoneal acyl-ghrelin administration on food consumption and plasma growth hormone (GH) concentrations in WT (n = 8) and KO (n = 8) rats. We also analyzed locomotion, food consumption, and body fat composition in these animals. Body weight was monitored from early development to adulthood.
The RNAscope analysis revealed an abundance of GHSR mRNA expression in the hypothalamus, midbrain, and hippocampus in WTs, and no observed probe binding in KOs. Ghrelin administration increased plasma GH levels (p = 0.0067) and food consumption (p = 0.0448) in WT rats but not KOs. KO rats consumed less food overall at basal conditions and weighed significantly less compared with WTs throughout development (p = 0.0001). Compared with WTs, KOs presented higher concentrations of brown adipose tissue (BAT; p = 0.0322).
We have verified GHSR deletion in our KO model using histological, physiological, neuroendocrinological, and behavioral measures. Our findings indicate that GHSR deletion in rats is not only associated with a lack of response to ghrelin, but also associated with decreases in daily food consumption and body growth, and increases in BAT. This GHSR KO Wistar rat model provides a novel tool for studying the role of the ghrelin system in obesity and in a wide range of medical and neuropsychiatric disorders.
Preclinical evidence suggests that ghrelin, a peptide synthesized by endocrine cells of the stomach and a key component of the gut-brain axis, is involved in alcohol seeking as it modulates both ...central reward and stress pathways. However, whether and how ghrelin administration may impact alcohol intake in humans is not clear. For, we believe, the first time, this was investigated in the present randomized, crossover, double-blind, placebo-controlled, human laboratory study. Participants were non-treatment-seeking alcohol-dependent heavy-drinking individuals. A 10-min loading dose of intravenous ghrelin/placebo (3 mcg kg
) followed by a continuous ghrelin/placebo infusion (16.9 ng/kg/min) was administered. During a progressive-ratio alcohol self-administration experiment, participants could press a button to receive intravenous alcohol using the Computerized Alcohol Infusion System. In another experiment, brain functional magnetic resonance imaging was conducted while participants performed a task to gain points for alcohol, food or no reward. Results showed that intravenous ghrelin, compared to placebo, significantly increased the number of alcohol infusions self-administered (percent change: 24.97±10.65, P=0.04, Cohen's d=0.74). Participants were also significantly faster to initiate alcohol self-administration when they received ghrelin, compared to placebo (P=0.03). The relationships between breath alcohol concentration and subjective effects of alcohol were also moderated by ghrelin administration. Neuroimaging data showed that ghrelin increased the alcohol-related signal in the amygdala (P=0.01) and modulated the food-related signal in the medial orbitofrontal cortex (P=0.01) and nucleus accumbens (P=0.08). These data indicate that ghrelin signaling affects alcohol seeking in humans and should be further investigated as a promising target for developing novel medications for alcohol use disorder.
•Brain expression of oxytocin and its receptor genes in patients with major psychiatric disorders has not been well studied outside the hypothalamus.•We measured expression of mRNA for oxytocin ...receptor in the dorsolateral prefrontal cortex of postmortem brains using quantitative polymerase chain reaction in a total of 581 individuals who were diagnosed with major depressive disorder (n = 135), bipolar disorder (n = 57), schizophrenia/schizoaffective disorder (n = 169), or who were control subjects (n = 220).•Diagnoses of major depressive disorder and bipolar disorder were associated with significantly increased oxytocin receptor mRNA levels in the dorsolateral prefrontal cortex.
There is growing interest in oxytocin as a putative treatment for various psychiatric disorders including major depressive disorder, bipolar disorder and schizophrenia/schizoaffective disorder. However, potential alterations in the endogenous brain oxytocin system in these disorders are poorly characterized. Brain expression of oxytocin and its receptor genes in patients with these psychiatric disorders has not been well studied outside the hypothalamus. We measured expression of mRNA for oxytocin and its receptor in the dorsolateral prefrontal cortex of postmortem brains using quantitative polymerase chain reaction in a total of 581 individuals. These individuals either were diagnosed with major depressive disorder (n = 135), bipolar disorder (n = 57), schizophrenia/schizoaffective disorder (n = 169), or were control subjects, defined as individuals with no lifetime history of any of these disorders (n = 220). Diagnoses of major depressive disorder and bipolar disorder were associated with significantly increased oxytocin receptor mRNA levels in the dorsolateral prefrontal cortex. This finding is discussed in light of the extant literature on the dysregulation of oxytocin signaling in individuals with major psychiatric disorders.
We evaluated the effect of different concentrations of the esterase inhibitor, AEBSF, and acid treatment on acyl-ghrelin stability in human plasma samples subjected to a freeze/thaw cycle.
Four ...plasma samples were collected from each donor and treated with the following concentrations of AEBSF: 2 mg/ml, 1 mg/ml, 0.6 mg/ml, and 0 mg/ml. For each plasma tube collected, half of the aliquots were treated with HCl and stored at -80°C before measuring acyl-ghrelin concentration using enzyme-linked immunosorbent assay (ELISA).
Treatment with 1 mg/ml AEBSF + HCl resulted in significantly higher acyl-ghrelin levels compared to all other treatments except 2 mg/ml AEBSF + HCl or 0.6 mg/ml AEBSF + HCl. While all HCl-treated samples had higher acyl-ghrelin levels than their AEBSF-matched un-acidified samples, only samples treated with 1 mg/ml AEBSF significantly differed in acyl-ghrelin levels as a result of HCl treatment.
Our results suggest the use of 1 mg/ml AEBSF with HCl for optimal acyl-ghrelin stability in human plasma samples subjected to a freeze/thaw cycle before assay. Given that 2 mg/ml and 0.6 mg/ml AEBSF + HCl did not significantly differ from 1 mg/ml AEBSF + HCl, our data suggest that the use of AEBSF with HCl more potently prevents de-acylation of ghrelin than either treatment alone.
Summary Background Intervention to achieve alcohol abstinence represents the most effective treatment for alcohol-dependent patients with liver cirrhosis; however, anticraving drugs might worsen ...liver disease. We aimed to investigate the effectiveness and safety of baclofen in achieving and maintaining alcohol abstinence in patients with liver cirrhosis. Methods Between October, 2003, and November, 2006, 148 alcohol-dependent patients with liver cirrhosis were referred to the Institute of Internal Medicine, Rome, Italy. 84 were randomly allocated either oral baclofen or placebo for 12 weeks. Primary outcome was proportion of patients achieving and maintaining alcohol abstinence. Measures of this outcome were total alcohol abstinence and cumulative abstinence duration, which were assessed at outpatient visits. Relapse was defined as alcohol intake of more than four drinks per day or overall consumption of 14 or more drinks per week over a period of at least 4 weeks. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov , number NCT00525252. Findings Of 42 patients allocated baclofen, 30 (71%) achieved and maintained abstinence compared with 12 (29%) of 42 assigned placebo (odds ratio 6·3 95% CI 2·4–16·1; p=0·0001). The number of dropouts (termination of treatment) did not differ between the baclofen (6/42 14%) and placebo (13/42 31%) groups (p=0·12). Cumulative abstinence duration was about twofold higher in patients allocated baclofen than in those assigned placebo (mean 62·8 SE 5·4 vs 30·8 5·5 days; p=0·001). No hepatic side-effects were recorded. Interpretation Baclofen is effective at promoting alcohol abstinence in alcohol-dependent patients with liver cirrhosis. The drug is well tolerated and could have an important role in treatment of these individuals.
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