Leptin: a modulator of alcohol craving?

Cluster analysis in gambling disorder based on sociodemographic, neuropsychological, and neuroendocrine features regulating energy homeostasis

BACKGROUND

The heterogeneity of gambling disorder (GD) has led to the identification of different subtypes, mostly including phenotypic features, with distinctive implications on the GD severity and treatment outcome. However, clustering analyses based on potential endophenotypic features, such as neuropsychological and neuroendocrine factors, are scarce so far.

AIMS

This study firstly aimed to identify empirical clusters in individuals with GD based on sociodemographic (i.e., age and sex), neuropsychological (i.e., cognitive flexibility, inhibitory control, decision making, working memory, attention, and set-shifting), and neuroendocrine factors regulating energy homeostasis (i.e., leptin, ghrelin, adiponectin, and liver-expressed antimicrobial peptide 2, LEAP-2). The second objective was to compare the profiles between clusters, considering the variables used for the clustering procedure and other different sociodemographic, clinical, and psychological features.

METHODS

297 seeking-treatment adult outpatients with GD (93.6% males, mean age of 39.58 years old) were evaluated through a semi-structured clinical interview, self-reported psychometric assessments, and a protocolized neuropsychological battery. Plasma concentrations of neuroendocrine factors were assessed in peripheral blood after an overnight fast. Agglomerative hierarchical clustering was applied using sociodemographic, neuropsychological, and neuroendocrine variables as indicators for the grouping procedure. Comparisons between the empirical groups were performed using Chi-square tests (χ2) for categorical variables, and analysis of variance (ANOVA) for quantitative measures.

RESULTS

Three-mutually-exclusive groups were obtained, being neuropsychological features those with the greatest weight in differentiating groups. The largest cluster (Cluster 1, 65.3%) was composed by younger males with strategic and online gambling preferences, scoring higher on self-reported impulsivity traits, but with a lower cognitive impairment. Cluster 2 (18.2%) and 3 (16.5%) were characterized by a significantly higher proportion of females and older patients with non-strategic gambling preferences and a worse neuropsychological performance. Particularly, Cluster 3 had the poorest neuropsychological performance, especially in cognitive flexibility, while Cluster 2 reported the poorest inhibitory control. This latter cluster was also distinguished by a poorer self-reported emotion regulation, the highest prevalence of food addiction, as well as a metabolic profile characterized by the highest mean concentrations of leptin, adiponectin, and LEAP-2.

CONCLUSIONS

To the best of our knowledge, this is the first study to identify well-differentiated GD clusters using neuropsychological and neuroendocrine features. Our findings reinforce the heterogeneous nature of the disorder and emphasize a role of potential endophenotypic features in GD subtyping. This more comprehensive characterization of GD profiles could contribute to optimize therapeutic interventions based on a medicine of precision.

Novel paradigms for the gut-brain axis during alcohol withdrawal, withdrawal-associated depression, and craving in patients with alcohol use disorder

Introduction

Patients with alcohol use disorder (AUD) exhibit symptoms such as alcohol withdrawal, depression, and cravings. The gut-immune response may play a significant role in manifesting these specific symptoms associated with AUD. This study examined the role of gut dysfunction, proinflammatory cytokines, and hormones in characterizing AUD symptoms.

Methods

Forty-eight AUD patients [men (n = 34) and women (n = 14)] aged 23-63 years were grouped using the Clinical Institute Withdrawal Assessment of Alcohol Scale (CIWA) as clinically significant (CS-CIWA [score > 10] [n = 22]) and a clinically not-significant group (NCS-CIWA [score ≤ 10] [n = 26]). Clinical data (CIWA, 90-day timeline followback [TLFB90], and lifetime drinking history [LTDH]) and blood samples (for testing proinflammatory cytokines, hormones, and markers of intestinal permeability) were analyzed. A subset of 16 AUD patients was assessed upon admission for their craving tendencies related to drug-seeking behavior using the Penn-Alcohol Craving Score (PACS).

Results

CS-CIWA group patients exhibited unique and significantly higher levels of adiponectin and interleukin (IL)-6 compared to NCS-CIWA. In the CS group, there were significant and high effects of association for the withdrawal score with gut-immune markers (lipopolysaccharide [LPS], adiponectin, IL-6, and IL-8) and for withdrawal-associated depression with gut-immune markers (scored using MADRS with LPS, soluble cells of differentiation type 14 [sCD14], IL-6, and IL-8). Craving (assessed by PACS, the Penn-Alcohol Craving Scale) was significantly characterized by what could be described as gut dysregulation (LBP [lipopolysaccharide binding protein] and leptin) and candidate proinflammatory (IL-1β and TNF-α) markers. Such a pathway model describes the heavy drinking phenotype, HDD90 (heavy drinking days past 90 days), with even higher effects (R2 = 0.955, p = 0.006) in the AUD patients, who had higher ratings for cravings (PACS > 5).

Discussion

The interaction of gut dysfunction cytokines involved in both inflammation and mediating activity constitutes a novel pathophysiological gut-brain axis for withdrawal symptoms and withdrawal-associated depression and craving symptoms in AUD. AUD patients with reported cravings show a significant characterization of the gut-brain axis response to heavy drinking.

Trial registration

ClinicalTrials.gov, identifier: NCT# 00106106.

Fasudil may alleviate alcohol-induced astrocyte damage by modifying lipid metabolism, as determined by metabonomics analysis

Alcohol dependence is a chronic, relapsing encephalopathy characterized by compulsive craving for alcohol, loss of control over alcohol use, and the presence of negative emotions and physical discomfort when alcohol is unavailable. Harmful use of alcohol is one of the greatest risk factors for death, illness, and disability. Rho kinase inhibitors have neuroprotective effects. This study used metabonomics analysis to assess untreated astrocytes, astrocytes exposed to 75 mmol/L of alcohol, and astrocytes exposed to 75 mmol/L of alcohol and treated with 15 µg/mL fasudil for 24 h. One of the clearest differences between the alcohol-exposed and fasudil-treated alcohol-exposed groups was the abundance of lipids and lipid-like molecules, although glycerophospholipid metabolism was comparable in both groups. Our findings show that fasudil may alleviate alcohol-induced astrocyte damage by modifying lipid metabolism, providing a new approach for preventing and treating alcohol dependence.

Confusion of Alcohol Craving With Food Hunger in Alcohol-Dependent Individuals Entering In-Patient Drug Treatment

AIM

To identify the distinguishing characteristics of alcohol dependent patients who confuse alcohol cravings with pre-meal hunger.

METHODS

Data were collected at interview on sociodemographic status, clinical status and anthropometry in 179 patients (163 men and 16 women) undergoing in-patient treatment for alcohol dependence.

RESULTS

A comparison of the patient subgroups studied showed that patients who did not confuse, and those who did confuse, alcohol craving with pre-meal hunger differed significantly in terms of alcohol craving scale scores (9 vs. 4 points). Patients confusing alcohol cravings with pre-meal hunger were more likely to recognize that experiencing severe pre-meal hunger can cause relapse (67.9 vs. 22.8%) and that not being able to distinguish between the sensations under study also increases the risk of breaking abstinence (75.0% vs. 50.4%). This was independent of severity of dependence and intensity of recent alcohol consumption.

CONCLUSIONS

Alcohol-dependent persons who confuse alcohol craving with pre-meal hunger differ from those who do not confuse these hunger pangs in terms of feeling stronger alcohol craving and more frequent occurrence of symptoms accompanying the feeling of alcohol craving during pre-meal hunger. At the start of treatment for alcohol withdrawal, alcohol-dependent individuals who report confusing alcohol cravings with pre-meal hunger are less confident of maintaining abstinence. This is relevant to treatment. The role of possible confounders (depressive symptoms, cognitive and educational deficiency) could not be elucidated definitively.

The Relationship between Binge Drinking and Binge Eating in Adolescence and Youth: A Systematic Review and Meta-Analysis

Adolescence and youth are critical periods in which alcohol consumption is usually initiated, especially in the form of binge drinking. In recent years, it is increasingly common to find adolescents and young people who also present binge behaviors towards unhealthy food with the aim of alleviating their anxiety (emotional eating) and/or because of impulsive personality. Despite the social and health relevance of this issue, it remains scarcely studied and more preventive research needs to be developed. Our meta-analysis study aimed to evaluate the relationship and co-occurrence of both binge behaviors during adolescence and young adulthood to clarify the link between binge drinking and eating. Selective literature search on different online databases was performed. We identified discrete but significant results regarding the direct association between binge drinking and binge eating in correlation coefficients and odds ratio. Future research should focus on the common psychological background and motives behind these problematic behaviors owing to their clinical implications for effective prevention and treatment.

Investigating associations between appetite-regulating hormones, aggression and craving in males with cannabis use disorder

BACKGROUND

Aggression and craving are common and important withdrawal symptoms in cannabis use disorder. The present study investigated the association between appetite-regulating hormones, aggression, and craving during cannabis withdrawal syndrome (CWS).

METHODS

Fifty-six male subjects diagnosed with cannabis withdrawal and 45 healthy males were included in the study. The Substance Craving Scale, the Buss-Perry Aggression Questionnaire, and the State-Trait Anxiety Inventory were implemented at baseline. Blood samples were drawn to measure ghrelin, leptin, adiponectin, and resistin levels in the serum. Then, the Point Subtraction Aggression Paradigm (PSAP) was applied. Bloodwork and psychometric assessment procedures were re-implemented after the PSAP. At the 7-day follow-up, psychometric assessments and hormone measurements were repeated in the CWS group.

RESULTS

Baseline serum ghrelin and adiponectin levels were lower in the CWS group than controls at baseline. After PSAP, there was a significant increase in ghrelin levels of patients with CWS compared to controls. Patients yielded higher aggression scores, while there was no significant correlation between hormonal changes and PSAP findings. At 7-day follow, ghrelin and resistin levels significantly increased, while serum leptin decreased in patients with CWS. Finally, there was a positive association between craving and resistin levels.

CONCLUSIONS

Our results present the changes in appetite-regulating hormones. Long-term follow-up studies are needed to shed light on neuroendocrinological aspects of cannabis withdrawal.

Reduction of impulsivity in patients receiving deep transcranial magnetic stimulation treatment for obesity

PURPOSE

Aims of the present study were to investigate a wide array of psychological symptoms through validated psychometric tests, before and after 5 weeks of deep Transcranial Magnetic Stimulation (dTMS) in individuals with obesity, and to identify possible relationships with neuroendocrine parameters.

METHODS

Forty-five patients with obesity (33 F, 12 M; age 48.8 ± 9.9 years; body wt 97.6 ± 14.2 Kg; BMI 36.2 ± 4.2) were randomized into two groups: 26 received high frequency (HF) dTMS and 19 Sham stimulation for 5 weeks. At baseline and after the 5-week treatment, all patients underwent the following psychometric evaluations: Food Cravings Questionnaire-Trait (FCQ-T) and its subscales, Barratt Impulsiveness Scale-11 (BIS-11), State and Trait Anxiety Inventory (STAI-y1 and STAI-y2), and Beck Depression Inventory (BDI). Hormonal and neuroendocrine markers were assessed at the first and last dTMS session.

RESULTS

By adjusting for baseline variables and treatment arms, a significant decrease in body wt and BMI was found in HF group, both with univariate (p = 0.019) and multivariate analyses (p = 0.012). Impulsivity significantly decreased in HF group, both with univariate (p = 0.031) and multivariate analyses (p = 0.011). A positive association between the impulsivity score change and the leptin level variation (p = 0.031) was found.

CONCLUSION

The decrease of impulsivity together with the BMI reduction in individuals with obesity, treated with real stimulation, suggests that impulsivity may be a risk factor for obesity. Treatment with dTMS revealed to be effective in reducing both BMI and impulsivity by enhancing inhibitory capacity of Pre-Frontal Cortex (PFC), and modulating neuroendocrine system, especially leptin.

Differences in the promoter methylation of atrial natriuretic peptide and vasopressin in alcohol use disorder. A longitudinal case-control-study during withdrawal therapy

BACKGROUND

Both atrial natriuretic peptide (ANP) and vasopressin (VP) influence alcohol intake and withdrawal as well as craving and are also regulated by epigenetic factors. Disturbances in expression and promoter methylation status have been described in patients suffering from alcohol use disorder and alcohol withdrawal therapy.

OBJECTIVES

In this study, we wanted to map the progression of cytosine-phosphatidyl-guanine (CpG) methylation of the respective gene promoter of ANP and VP immediately after starting alcohol withdrawal therapy when compared with healthy controls METHODS: We recruited 34 males suffering from alcohol addiction or harmful use alongside 43 healthy male controls. Blood samples for methylation analyses were drawn on days 1, 2, 3, 4, and 7-10.

RESULTS

There was no difference in mean methylation for both VP and ANP during withdrawal. There was no difference at the ANP CpG-sites after correction for multiple testing. Regarding VP, methylation was significantly higher at CpG 033, CpG 064, CpG 103, CpG 118, and CpG 194 and significantly lower at CpG 053, CpG 060, and CpG 214 when compared to healthy controls. Via in silico analysis, we identified transcription factor binding sites that could potentially influence methylation-dependent gene transcription.

CONCLUSIONS

While there was no change in methylation status during withdrawal, significant differences in average methylation of specific CpG sites were observed for VP. We also identified the role of transcription factors in the context of promoter methylation as one potential mechanism that could explain the differences in VP levels between alcohol-dependent patients and healthy controls.

Body mass index and serum levels of soluble leptin receptor are sex-specifically related to alcohol binge drinking behavior

OBJECTIVE

Binge drinking is a highly prevalent behavior in adolescents and young adults and a risk factor to develop alcohol use disorder. Body mass index (BMI) and blood levels of leptin peptide and its soluble receptor have been implicated in alcohol use disorder; however, their role in binge drinking remains to be investigated.

METHOD

We studied associations of BMI, serum levels of soluble leptin receptor (ObRe) and leptin as well as the free leptin index with binge drinking in 93 male and 99 female young adults.

RESULTS

In men, binge drinkers showed significantly higher BMI (kg/m²) than non-binge drinkers (23.67 vs. 22.08) and higher BMI correlated significantly with more severe binge drinking episodes (ρ = 0.251). In women, we found significantly higher ObRe (ng/ml) / BMI (kg/m²) values in binge drinkers than in non-binge drinkers (0.52 vs. 0.44) and ObRe/BMI values correlated significantly with more severe binge drinking episodes (ρ = 0.210).

CONCLUSION

This study confirms that higher BMI associates with binge drinking in men and shows for the first time a role of ObRe/BMI in binge drinking in women. Our data emphasize the importance of further research in the field of metabolic markers and implications in neurobiological processes of binge drinking.

A neuroimaging investigation into the role of peripheral metabolic biomarkers in the anticipation of reward in alcohol use

BACKGROUND

The relationship between alcohol use and metabolism has focused on the effects of alcohol use on metabolic factors. Metabolic factors, such as triglycerides, cholesterol, and glucose, have been shown to be associated with increased risk for heavy alcohol consumption and alcohol use disorder (AUD). It's been suggested that changes in metabolic factors may play a role in reward seeking behaviors and pathways. Studies on feeding behavior and obesity revealed the role of triglycerides in neural response to food cues in neurocircuitry regulating reward and feeding behaviors. This study aimed to explore the relationship of peripheral metabolism, alcohol use, and reward processing in individuals that use alcohol.

METHODS

Ninety participants from a previously collected dataset were included in the analysis. Participants were treatment seeking, detoxified individuals with AUD and healthy individuals without AUD, with the following metabolic biomarkers: triglyceride, glucose, high- and low-density cholesterol, and HbA1c levels. Participants completed a neuroimaging version of the Monetary Incentive Delay task (MID).

RESULTS

Correlations on peripheral metabolic biomarkers, alcohol use, and neural activity during reward anticipation and outcome during the MID task were not significant. Mediation models revealed triglycerides and high-density cholesterol had significant effects on left anterior insula during anticipation of potential monetary loss and this effect was not mediated by alcohol use.

CONCLUSION

Limbic recruitment by anticipation of monetary rewards revealed an independent relationship with peripheral metabolism and was not affected by individual differences in alcohol use, despite the effects of alcohol use on metabolic markers and reward processing neural circuitry.

Dietary fiber deficiency as a component of malnutrition associated with psychological alterations in alcohol use disorder

BACKGROUND & AIMS

Chronic alcohol consumption can cause malnutrition that may contribute to alcohol-induced organ injury and psychological disorders. We evaluated the link between nutrient intake, especially dietary fibers (DF) and different parameters reflecting mental health and well being, namely anxiety, depression, alcohol craving, sociability, fatigue and intestinal comfort in alcohol use disorder (AUD) patients.

METHODS

Cross-sectional data from 50 AUD patients, hospitalized for a 3-week detoxification program were used. Three 24-h recalls allowed to calculate dietary habits and nutrient intakes, that was also assessed in healthy subjects (HS). Diet quality was measured using the NOVA score. Psychological factors and intestinal discomfort were evaluated using validated self-administered questionnaires.

RESULTS

Energy intake (excluding alcoholic beverage), total fat, monounsaturated and polyunsaturated fatty acids, protein and DF intakes were lower in AUD subjects compared to HS. Ninety percent of patients had a DF intake below the recommendation. AUD patients consumed more than twice as much ultra-processed food than HS. Fructan intake was negatively associated with anxiety (p = 0.04) adjusted for main confounders. Total DF, insoluble, soluble DF and galacto-oligosaccharide intakes were associated with higher sociability score. Soluble DF intake was associated with better satisfaction of bowel function (p = 0.02) and a lower intestinal discomfort (p = 0.04).

CONCLUSIONS

This study reveals that insufficient DF intake is part of AUD-related malnutrition syndrome, and is associated with higher anxiety, lower sociability score and intestinal discomfort. Our results suggest that an adequate intake of DF might be beneficial for recovery from AUD.

TRIAL REGISTRATION

NCT03803709, https://clinicaltrials.gov/ct2/show/NCT03803709.

Effect of Transcutaneous Auricular Vagus Nerve Stimulation on Protracted Alcohol Withdrawal Symptoms in Male Alcohol-Dependent Patients

Protracted alcohol withdrawal symptoms (PAWS), characterized by the presence of substance-specific signs and symptoms (including anxiety, irritability, mood instability, insomnia, and cravings), make alcohol abstinence difficult and increase the risk of relapse in recovering alcoholics. The goal of this study was to evaluate the effect of transcutaneous auricular vagus nerve stimulation (taVNS) on PAWS and plasma brain-derived neurotrophic factor (BDNF), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and leptin levels in patients with alcohol dependency. A total of 114 patients with alcohol dependence were randomly divided into two groups: the treatment group and the control group. The patients in the treatment group were treated with taVNS of the bilateral auricular concha using an ear vagus nerve stimulator. The Pennsylvania Alcohol Craving Scale was used to evaluate the extent of craving for alcohol. The Self-Rating Anxiety Scale and Self-Rating Depression Scale (SDS) were used to evaluate the extent of anxiety and depression symptoms, respectively. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality. Enzyme-linked immunosorbent assay was used to measure plasma BDNF, IL-6, TNF-α, and leptin levels. The results showed that the SDS and PSQI scores were significantly lower in the treatment group than in the control group. Moreover, compared with the control group, the average BDNF levels in the treatment group were significantly increased. These results suggest that taVNS could improve the depression symptoms and sleep quality in alcohol-dependent patients after withdrawal, which might be related to the upregulation of plasma BDNF levels.

Leptin Gene and Leptin Receptor Gene Polymorphisms in Alcohol Use Disorder: Findings Related to Psychopathology

Comorbidity between alcohol use disorder (AUD) and other addictive and psychiatric disorders is highly prevalent and disabling; however, the underlying biological correlates are not fully understood. Leptin is a peptide hormone known for its role in energy homeostasis and food intake. Furthermore, leptin plays a key role in the activity of the hypothalamic-pituitary-adrenal (HPA) axis and of several neurotransmitter systems that regulate emotionality and behavior. However, human studies that have investigated circulating leptin levels in relation to AUD and affective disorders, such as anxiety and depression, are conflicting. Genetic-based analyses of the leptin gene (LEP) and leptin receptor gene (LEPR) have the potential of providing more insight into the potential role of the leptin system in AUD and comorbid psychopathology. The aim of the current study was to investigate whether genotypic variations at LEP and LEPR are associated with measures of alcohol use, nicotine use, anxiety, and depression, all of which represent common comorbidities with AUD. Haplotype association analyses were performed, using data from participants enrolled in screening and natural history protocols at the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Analyses were performed separately in European Americans and African Americans due to the variation in haplotype diversity for most genes between these groups. In the European American group, one LEP haplotype (EB2H4) was associated with lower odds of having a current AUD diagnosis, two LEPR haplotypes (EB7H3, EB8H3) were associated with lower cigarette pack years and two LEPR haplotypes (EB7H2, EB8H2) were associated with higher State-Trait Anxiety Inventory (STAI-T) scores. In the African American group, one LEP haplotype (AB2H8) was associated with higher cigarette pack years and one LEP haplotype (AB3H2) was associated with lower Fagerström Test for Nicotine Dependence (FTND) scores. Overall, this study found that variations in the leptin and leptin receptor genes are associated with measures of alcohol use, nicotine use, and anxiety. While this preliminary study adds support for a role of the leptin system in AUD and psychopathologies, additional studies are required to fully understand the underlying mechanisms and potential therapeutic implications of these findings.

Interoception and alcohol addiction: Vagotomy induces long-lasting suppression of relapse-type behavior

Drug addictions are chronic mental disorders characterized by compulsive drug seeking and drug use, despite their negative consequences. It is a priority to find therapeutic alternatives to prevent relapse, as there are still no treatments that can ensure abstinence. One of the neural systems implicated in the appearance of the states of discomfort that motivate relapse is the interoceptive system, which oversees our internal body states. However, less attention has been given to the peripheral components of the interoceptive system and their role in addictions. Within these pathways, the vagus nerve represents one of the main visceral afferents of the interoceptive system. We hypothesized that the interruption of visceral afferent pathways would decrease the motivational effects of the drug, thereby either decreasing or preventing drug cravings. To test this idea, we used rats of a high-alcohol-drinking line and measured the effect that vagus nerve resection had on the relapse-like alcohol drinking, expressed as the alcohol deprivation effect, a phenomenon that has been linked to addiction-related events such as alcohol cravings. We found that even though vagotomy completely eliminates the effect of alcohol deprivation, it has no impact on water consumption or animal weight. These results give us valuable information about the relationship between the autonomic nervous system and alcohol use disorders and allow us to propose new clinical research that might have translational options.

The Impact of Appetite-Regulating Neuropeptide Leptin on Alcohol Use, Alcohol Craving and Addictive Behavior: A Systematic Review of Preclinical and Clinical Data

AIMS

The appetite regulating hormone leptin, which is mainly secreted from adipose tissue, is an important regulator of food intake and modulator of reward-driven behavior. Leptin exerts its biological actions via binding to the leptin receptor, which is expressed in the hypothalamus, but also in the hippocampus, the amygdala and the substantia nigra. In the ventral tegmental area (VTA), leptin attenuates the firing rate of dopaminergic neurons that project to the Nucleus accumbens (NAc), which serves as relay to other brain areas of the "addiction network", such as the prefrontal cortex. This suggests that leptin plays a role in the processing of rewards in the context of substance use disorders such as alcohol use disorder, especially through attenuation of dopaminergic activity in the mesolimbic reward system. This supports the plausibility of leptin's potential effects in alcohol use disorder.

METHODS

We searched MEDLINE from 1990 to February 2020. All abstracts were screened for relevance and we only included publications reporting original data with a full text available in English language. Studies that did not report leptin-data, reviews or case reports/series were not included.

RESULTS

We identified a total of N=293 studies of whom a total of N=55 preclinical and clinical studies met the specified criteria. N=40 studies investigated the effects of alcohol on leptin plasma levels, N=9 studies investigated the effects of leptin on alcohol craving and N=6 studies investigated the effects of leptin on relapse and alcohol consumption.

CONCLUSIONS

In this review of preclinical and clinical data, we assess the role of leptin in alcohol use and the development and maintenance of an alcohol use disorder, alcohol craving and relapse. Integrating the existing preclinical and clinical data on leptin may reveal new and innovative targets for the treatment of substance use disorders in the future.

Leptin levels in alcohol dependent patients and their relationship with withdrawal and craving

OBJECTIVE

Association between leptin plasma levels and alcohol craving has been seen previously. This study aims to research this correlation in a different population while comparing this correlation with respect to hyper-excitable state of alcohol withdrawal.

METHODS

25 patients of alcohol dependence were assessed for withdrawal symptoms and craving for alcohol. Leptin levels were measured on 1^st day, @ the end of 1^st week, @ the end of 3^rd week of stopping alcohol. Withdrawal was assessed using CIWA-A at day 1 and day 7, craving was assessed using PENN's scale of craving at week 1 and week 3. Control group consisted of 15 first degree relatives.

RESULTS

Leptin levels [t (38) = 2.95, p = 0.005] was significantly higher in alcohol dependent patients. Levels had no significant correlation with alcohol withdrawal scores [Leptin/BMI and CIWA Ar: r = 0.18, p = 0.40 on day 1] but had positive correlation with craving scores [Leptin/BMI and PACS: r = 0.684, p = 0.001].

CONCLUSION

This study shows that leptin, known for balancing the energy homeostasis of body, also seem to play a role in pathways of drug dependence and craving. This relation is independent of stress hormone axis.

Serum lipids, leptin, and soluble leptin receptor in alcohol dependence: A cross-sectional and longitudinal study

OBJECTIVE

Alcohol dependence affects metabolic processes. Further research is needed to apply this knowledge clinically. In this study, possible differences in serum lipids and/or leptin activities between alcohol-dependent in-patients and healthy controls and possible associations with alcohol-related blood parameters and with prospective outcomes in alcohol dependence were assessed sex-specifically.

METHOD

We measured and compared (median) serum lipids (triglycerides and total, HDL, and LDL cholesterol) and leptin activities (leptin, soluble leptin receptor [ObRe], and free leptin index) in 200 (males 56.5 %) early-abstinent alcohol-dependent in-patients and 240 (males 55.4 %) healthy controls and assessed alcohol-related readmissions during a 24 -month post-inclusion period.

RESULTS

Male patients showed higher HDL cholesterol (61 versus 48 mg/dl), lower LDL/HDL ratios (2.06 versus 3.04), and lower free leptin index (0.30 versus 0.59) at study inclusion compared to healthy controls. In patients, ObRe levels were higher than in controls and decreased from inclusion to the second study-visit (at median 5 days later; males: 16.7-13.8 versus 11.0 ng/ml; females: 17.0-13.4 versus 12.1 ng/ml). The free leptin index increased between the two time points in females (0.80 versus 1.20). Lipids and leptin activities correlated with carbohydrate-deficient transferrin levels and liver enzyme activities. None of the serum parameters were significantly associated with alcohol-related readmissions.

CONCLUSION

Our data support that serum lipid levels and leptin activities are involved in alcohol dependence. The parameters appear as possible indirect biomarkers for alcohol dependence.

Evidence of a Relationship Between Plasma Leptin, Not Nesfatin-1, and Craving in Male Alcohol-Dependent Patients After Abstinence

The goal of this study was to determine whether the plasma leptin, nesfatin-1, cortisol, brain-derived neurotrophic factor (BDNF), and inflammatory cytokines could be used as potential biomarkers for the degree of craving in the alcohol-dependent patients after 1 month of abstinence. A total of 83 patients with alcohol use disorder (AUD) and 61 healthy subjects were assessed. Patients with AUD were selected from Department of Material Dependence, Anhui Mental Health Center, and subjects in the control group were selected from healthy volunteers. The Alcohol Urge questionnaire Scale (AUQ) was used to evaluate the extent of craving for alcohol, and the Michigan Alcoholism Screening Test (MAST), the Fagerstrom Test for Nicotine Dependence (FTND), the Self-Rating Anxiety Scale (SAS), and the Self-Rating Depression Scale (SDS) were also assessed in patients with AUD. Enzyme-Linked Immunosorbent Assay (ELISA) was used for the measurement of plasma leptin, nesfatin-1, cortisol, BDNF, Interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-α (TNF-α) levels. Compare with healthy controls, the average leptin, leptin/BMI, IL-6, CRP, and TNF-α levels in patients with AUD were significantly increased, while the BDNF levels were significantly decreased. Moreover, the partial correlational analysis showed that the AUQ scores of the alcohol-dependent patients were positively correlated with the plasma leptin levels (r = 0.613, P < 0.001), rather than nesfatin-1 (r = 0.066, P = 0.569) after controlling for age as covariate. Furthermore, plasma nesfatin-1 levels were found to be correlated with the SDS scores (r = 0.366, P = 0.001) in the AUD group. In addition, plasma leptin levels were positively associated with the plasma IL-6 (r = 0.257, P = 0.033), CRP (r = 0.305, P = 0.011), and TNF-α (r = 0.311, P = 0.009) levels, and negatively associated with the BDNF levels (r = -0.245, P = 0.042) in patients with AUD. These results suggest that plasma leptin, but not nesfatin-1, might be a potential biomarker for the degree of craving in alcohol-dependent patients after 1 month of abstinence, the mechanism of which might be related to the dysfunction of the inflammatory cytokines and BDNF levels.

Effects of leptin and ghrelin on neural cue-reactivity in alcohol addiction: Two streams merge to one river?

Leptin and ghrelin and a "cross-talk" between both hormones were implicated in the pathophysiology of alcohol dependence, both modulating alcohol craving and drug-seeking. To date, the neurobiological mechanisms underlying those effects are still little-known. We thus investigated the effect of leptin and ghrelin on alcohol cue-induced brain response, alcohol craving and relapse risk in alcohol-dependent subjects. Seventy abstinent alcohol dependent individuals underwent a functional magnetic resonance imaging (fMRI) alcohol cue-reactivity task and patients` alcohol craving was assessed. Plasma levels of leptin, total and acylated, active ghrelin were measured prior to the fMRI session. Additionally, relapse data was collected during a three-month follow-up. Associations between hormone levels, mesolimbic cue-reactivity, alcohol craving and relapse risk were tested. Leptin levels showed a significant negative association to alcohol cue-induced brain response in the striatum and alcohol craving. In addition, there was a significant effect of leptin on time to first heavy relapse in which higher leptin levels predicted longer times to first heavy relapse. Moreover, positive associations between acylated ghrelin and increased cue-reactivity in bilateral insulae as well as increased craving for alcohol during the fMRI task were revealed. Leptin and acylated ghrelin show opposing effects on mesolimbic cue-reactivity and alcohol craving. We suspect that the reduced striatal cue-reactivity might be the neurobiological correlate of leptin's effect on relapse-risk. The reported results further support the relevance of appetite regulating hormones in the pathophysiology of addiction and their potential role as future treatment targets.

Serum inflammatory molecules and markers of neuronal damage in alcohol-dependent subjects after withdrawal

OBJECTIVES

Our aim is to describe changes in serum concentration for the pro-inflammatory factors TNF-α, IFN-γ, IL-1β, IL-8, IL-6, IL-10, IL-12 and MCP-1, for the satiety factor leptin and for factors associated with neuronal changes, neuron-specific enolase (NSE) and glial activation S100-beta protein (S100-β), and explore their association with abstinence in alcohol-dependent subjects after withdrawal.

METHODS

Serum sampling and clinical assessments from 115 alcohol-dependent subjects admitted to a psychiatric hospital for alcohol were repeated during the first 48 h of withdrawal (M0) and 1, 2, 4 and 6 months (M1, M2, M4 and M6) thereafter. Serum factors were determined with Luminex technology or by ELISA.

RESULTS

The levels of TNF-α, IL-1β, IL-8, IL-6, IL-12, MCP-1, and leptin decreased after withdrawal and remained low until M6, regardless of alcohol consumption. IFN-γ levels remained constant and IL-10 levels changed only slightly. NSE levels were not modified, whereas serum S100-β concentration increased significantly on M1 and then plateaued, regardless of abstinence status at 6 months.

CONCLUSIONS

Alcohol-dependent subjects present an inflammatory condition that is not dependent on alcohol consumption. An understanding of the changes in concentration of the various proteins considered here would provide insight into the physiology of withdrawal or dependence.

Plasma levels of leptin in patients with pathological gambling, internet gaming disorder and alcohol use disorder

Leptin has been suggested to be involved in the pathophysiology of addictive disorders via modulation of mesolimbic reward pathways. Previous studies in patients with substance use disorders (alcohol, tobacco, cocaine) found positive correlations of leptin blood levels with craving. Here, we investigated leptin blood levels in patients with non-substance related addictive disorders such as pathological gambling (PG) and internet gaming disorder (IGD) in comparison to patients with alcohol use disorder (AUD) and healthy controls. Plasma levels of leptin were measured in male patients with PG (n = 14), male patients with IGD (n = 11), male patients with AUD (n = 39) and male healthy controls (n = 12). Additionally, correlation analyses with blood levels of HPA axis hormones were performed. Leptin plasma levels of patients with PG, IGD or AUD and healthy controls did not differ significantly across groups. In patients with PG, leptin plasma levels were correlated with copeptin, a surrogate for arginine vasopressin. Our findings do not suggest an involvement of leptin in abstinent patients with AUD or in patients with active IGD. In patients with active PG, leptin blood levels were not related to craving for gambling, but leptin might be involved in PG via an interaction with the HPA axis.

Exogenous ghrelin administration increases alcohol self-administration and modulates brain functional activity in heavy-drinking alcohol-dependent individuals

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^-1) 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.

The bidirectional impacts of alcohol consumption and the metabolic syndrome: Cofactors for progressive fatty liver disease

Current medical practice artificially dichotomises a diagnosis of fatty liver disease into one of two common forms: alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). Together, these account for the majority of chronic liver diseases worldwide. In recent years, there has been a dramatic increase in the prevalence of obesity and metabolic syndrome within the general population. These factors now coexist with alcohol consumption in a substantial proportion of the population. Each exposure sensitises the liver to the injurious effects of the other; an interaction that drives and potentially accelerates the genesis of liver disease. We review the epidemiological evidence and scientific literature that considers how alcohol consumption interacts with components of the metabolic syndrome to exert synergistic or supra-additive effects on the development and progression of liver disease, before discussing how these interactions may be addressed in clinical practice.

Differential spontaneous recovery across cognitive abilities during detoxification period in alcohol-dependence

OBJECTIVE

There is a lack of consensus regarding the extent to which cognitive dysfunctions may recover upon cessation of alcohol intake by alcohol-dependents (AD), and the divergent findings are most likely due to methodological differences between the various studies. The present study was aimed at conducting a very strict longitudinal study of cognitive recovery in terms of assessment points, the duration of abstinence, control of age and duration of the addiction, and by use of individual analyses in addition to mean group comparisons. Our study further focused on the 2-3 week phase of alcohol detoxification that is already known to positively affect many biological, emotional, motivational, as well as neural variables, followed by longer-term therapies for which good cognitive functioning is needed.

METHODS

41 AD inpatients undergoing a detoxification program, and 41 matched controls, were evaluated twice in terms of five cognitive functions (i.e., short-term memory, working memory, inhibition, cognitive flexibility, and verbal fluency) within a three-week interval [on the first day (T1) and the 18th day (T2) of abstinence for AD patients]. Emotional (positive and negative affectivity and depression) and motivational (craving) variables were also measured at both evaluation times.

RESULTS

Although verbal fluency, short-term memory, and cognitive flexibility did not appear to be affected, the patients exhibited impaired inhibition and working memory at T1. While no recovery of inhibition was found to occur, the average working memory performance of the patients was comparable to that of the controls at T2. Improvements in emotional and motivational dimensions were also observed, although they did not correlate with the ones in working memory. Individual analysis showed that not all participants were impaired or recover the same functions.

CONCLUSIONS

While inhibition deficits appear to persist after 18 days of detoxification, deficits in working memory, which is a central component of cognition, are greatly reduced after alcohol detoxification. Individual differences in the trajectory of recovery do arise however, and it might be worth implementing individual assessments of impaired functions at the end of the detoxification phase in order to maximize the chances of success in longer-term treatments and abstinence.

Serum NUCB2/nesfatin-1 levels in different stages of alcohol dependence: Is there a relationship with craving?

INTRODUCTION

In the literature, the relationship between appetite regulating peptides and alcohol craving is on the debate.

AIM

This study aims to investigate serum level of NUCB2/nesfatin-1, which is discovered as appetite-related neuropeptide, in patients with alcohol dependence who were in craving and abstaining phase and to compare with healthy controls.

SETTINGS AND DESIGN

Research, Treatment, and Training Center for Alcohol and Substance Dependence, (AMATEM) Bakirkoy Training and Research Hospital for Psychiatry Neurology and Neurosurgery, Istanbul, case-control and prospective study design were used.

STATISTICAL ANALYSIS

Chi-square, Mann-Whitney U, paired samples, independent samples t- and Pearson correlation tests were used for analysis.

MATERIALS AND METHODS

Forty-three patients with alcohol dependence who have been admitted for detoxification and thirty healthy controls were included in the study. The blood samples were drawn after the 1^st day of admission and postdetoxification treatment in inpatients who reached to abstinence period and from 30 healthy controls. The Penn Alcohol Craving Scale and the Obsessive Compulsive Drinking Scale were applied to detect craving scores.

RESULTS

Initial serum NUCB2/nesfatin-1 levels in patients were significantly lower than in the healthy control group (P < 0.001). The NUCB2/nesfatin-1 level of initial phase was significantly lower than abstinence phase (P = 0.027). No correlation was found between craving scores and NUCB2/nesfatin-1 level (P > 0.05).

CONCLUSION

This study is the first that showed significant differences of serum NUCB2/nesfatin-1 level according to different stages of alcohol dependence. Plasma NUCB2/nesfatin-1 levels were lower in highest craving phase and tended to normalize after abstinence. Since we could not find a correlation between craving and NUCB2/nesfatin-1 levels, the increase of NUCB2/nesfatin-1 in abstinence phase might have been resulted from other reasons apart from craving.

The metabolic syndrome in patients with alcohol dependency: Current research and clinical implications

The relationship between alcohol dependency and disorders such as liver disease and cancer has been thoroughly researched. However, the effects of alcohol on cardiometabolic health remain controversial. Several reports found low to moderate alcohol consumption to be associated with a lower risk for cardiometabolic disorders. In contrast, excessive alcohol consumption has been related to an increased risk. Most of these studies were performed in non-clinical populations, therefore limiting the explanatory power to non-dependent patients. Only a few studies examined cardiovascular disorders and cardiovascular risk factors, in particular the metabolic syndrome (MetS), in alcohol dependent patients. We here present a narrative review of studies performed so far on the MetS in alcohol dependency, and provide current hypotheses on the association of alcohol dependency, appetite regulation and the development of the MetS.

Serum Insulin Levels Are Reduced by Intravenous Ghrelin Administration but Do Not Correlate with Alcohol Craving in Alcohol-Dependent Individuals

BACKGROUND

Increasing evidence supports a role for appetite-regulating pathways like ghrelin, insulin, and leptin in alcoholism. We previously reported that intravenous (i.v.) exogenous ghrelin increases alcohol craving. We also reported i.v. ghrelin reduces endogenous serum leptin, whose levels, in turn, negatively correlated with alcohol craving. Exogenous ghrelin administration decreases insulin secretion both in vitro and in vivo experiments. This study tested the hypothesis that i.v. ghrelin may also decrease endogenous serum insulin levels in alcoholic individuals. Additionally, we explored possible correlations between serum insulin and alcohol craving, since a correlation between insulin and alcohol craving was previously reported.

METHODS

This was a double-blind, placebo-controlled human laboratory study ( n =43). Non-treatment-seeking, alcohol-dependent, heavy drinkers were randomized to receive i.v. ghrelin or placebo, followed by an alcohol cue-reactivity procedure.

RESULTS

There was a main effect for i.v. ghrelin, compared to placebo in reducing serum insulin ( P <.05). There was also a time effect ( P <.001) but not ghrelin x time interaction ( P >.05). We did not find a correlation between the reduction of serum insulin and alcohol craving ( P >.05). The change in serum insulin was consistent with a parallel reduction in serum connective-peptide in the ghrelin group compared with placebo, although this difference did not reach statistical significance ( P =.076). No similar effects were found for other glucose-regulating hormones analyzed i.e. glucagon, glucagon-like peptide-1, and gastric inhibitory peptide ( P s>.05).

CONCLUSIONS

These findings indicate i.v. ghrelin administration has an effect on reducing serum insulin in alcohol-dependent individuals; however, the reduction of insulin did not correlate with changes in alcohol cue-elicited craving. We speculate that, unlike for leptin, the interactions between ghrelin and insulin relationship are limited at the peripheral level. However, mechanistic studies are needed to investigate this hypothesis.

Changes in the female arcuate nucleus morphology and neurochemistry after chronic ethanol consumption and long-term withdrawal

Ethanol is a macronutrient whose intake is a form of ingestive behavior, sharing physiological mechanisms with food intake. Chronic ethanol consumption is detrimental to the brain, inducing gender-dependent neuronal damage. The hypothalamic arcuate nucleus (ARN) is a modulator of food intake that expresses feeding-regulatory neuropeptides, such as alpha melanocyte-stimulating hormone (α-MSH) and neuropeptide Y (NPY). Despite its involvement in pathways associated with eating disorders and ethanol abuse, the impact of ethanol consumption and withdrawal in the ARN structure and neurochemistry in females is unknown. We used female rat models of 20% ethanol consumption for six months and of subsequent ethanol withdrawal for two months. Food intake and body weights were measured. ARN morphology was stereologically analyzed to estimate its volume, total number of neurons and total number of neurons expressing NPY, α-MSH, tyrosine hydroxylase (TH) and estrogen receptor alpha (ERα). Ethanol decreased energy intake and body weights. However, it did not change the ARN morphology or the expression of NPY, α-MSH and TH, while increasing ERα expression. Withdrawal induced a significant volume and neuron loss that was accompanied by an increase in NPY expression without affecting α-MSH and TH expression. These findings indicate that the female ARN is more vulnerable to withdrawal than to excess alcohol. The data also support the hypothesis that the same pathways that regulate the expression of NPY and α-MSH in long-term ethanol intake may regulate food intake. The present model of long-term ethanol intake and withdrawal induces new physiological conditions with adaptive responses.

Integration of reward signalling and appetite regulating peptide systems in the control of food-cue responses

Understanding the neurobiological substrates that encode learning about food-associated cues and how those signals are modulated is of great clinical importance especially in light of the worldwide obesity problem. Inappropriate or maladaptive responses to food-associated cues can promote over-consumption, leading to excessive energy intake and weight gain. Chronic exposure to foods rich in fat and sugar alters the reinforcing value of foods and weakens inhibitory neural control, triggering learned, but maladaptive, associations between environmental cues and food rewards. Thus, responses to food-associated cues can promote cravings and food-seeking by activating mesocorticolimbic dopamine neurocircuitry, and exert physiological effects including salivation. These responses may be analogous to the cravings experienced by abstaining drug addicts that can trigger relapse into drug self-administration. Preventing cue-triggered eating may therefore reduce the over-consumption seen in obesity and binge-eating disorder. In this review we discuss recent research examining how cues associated with palatable foods can promote reward-based feeding behaviours and the potential involvement of appetite-regulating peptides including leptin, ghrelin, orexin and melanin concentrating hormone. These peptide signals interface with mesolimbic dopaminergic regions including the ventral tegmental area to modulate reactivity to cues associated with palatable foods. Thus, a novel target for anti-obesity therapeutics is to reduce non-homeostatic, reward driven eating behaviour, which can be triggered by environmental cues associated with highly palatable, fat and sugar rich foods.

Influence of the leptin and cortisol levels on craving and smoking cessation

Leptin inhibits cortisol release and may increase the craving for cigarettes, hindering the process of smoking cessation. We evaluate the influence of the initial concentration of cortisol and serum leptin on craving and smoking status in individuals after one month of treatment for smoking cessation. The leptin concentration was adjusted by the Initial Body Mass Index (BMI) (leptin/BMI) and the initial percentage of body fat (%BF) (leptin/%BF). The craving was assessed using the Questionnaire of Smoking Urges-Brief (QSU-Brief). The QSU-Brief was assessed about a score of factor 1 (positive reinforcement by tobacco), and factor 2 (negative reinforcement by tobacco). Correlation was found between QSU-Brief (Factor 1 and 2) with the initial concentration of leptin/BF% among those who continued to smoke. There was a negative correlation between cortisol levels and leptin/%BF in individuals who remained smokers after 1 month. There was a positive correlation between leptin/BMI and leptin/%BF with the QSU-Brief (Factor 2) of 1 month in women who remained smokers (r=0.565; p=0.023) and the QSU-Brief (Factor 2) initial among the abstinent women (r=0.551; p=0.033). The highest concentrations of leptin were associated with greater craving and difficulty in achieve abstinence.

Leptin levels are reduced by intravenous ghrelin administration and correlated with cue-induced alcohol craving

Increasing evidence supports the role of appetite-regulating pathways, including ghrelin and leptin, in alcoholism. This study tested the hypothesis that intravenous exogenous ghrelin administration acutely decreases endogenous serum leptin levels, and that changes in leptin levels negatively correlate with alcohol craving. This was a double-blind, placebo-controlled human laboratory study. Non-treatment-seeking, alcohol-dependent, heavy drinkers (n=45) were randomized to receive intravenous ghrelin or placebo, followed by a cue-reactivity procedure, during which participants were exposed to neutral (juice) and alcohol trial cues. There was a main effect for intravenous ghrelin administration, compared with placebo, in reducing serum leptin levels (P<0.01). Post hoc analysis showed significant differences in serum leptin levels at the alcohol trial (P<0.05) that persisted at the end of the experiment (P<0.05). By contrast, there were no significant differences in serum leptin levels at the juice trial (P=not significant (NS)). The change of serum leptin level at the alcohol trial correlated with the increase in alcohol urge (P<0.05), whereas urge to drink juice was not correlated with the leptin change at the juice trial (P=NS). These findings provide preliminary evidence of ghrelin-leptin cross-talk in alcoholic individuals and suggest that their relationship may have a role in alcohol craving.

N-acetylcysteine prevents behavioral and biochemical changes induced by alcohol cessation in rats

N-acetylcysteine (NAC), a glutamate-modulating agent with antioxidant and anti-inflammatory properties, has been considered as a potential anti-addictive drug. Beneficial effects were reported for cocaine, cannabis, and tobacco addicts, but the effect of NAC in alcoholics or in alcohol animal models is unknown. The aggravation of alcohol withdrawal symptoms, such as anxiety, has been associated with increased levels of serum corticosterone and leptin. Thus, the aim of this study was to assess the effects of NAC on anxiety, as well as corticosterone and leptin serum levels, after cessation of chronic alcohol treatment in rats. Male Wistar rats were treated with 2 g/kg ethanol, twice daily, by gavage for 30 days; control animals received an appropriate dose of glucose to balance caloric intake. Rats were treated for 4 days with NAC (60 and 90 mg/kg, intra-peritoneally [i.p.]) or saline after alcohol cessation. Twenty-four hours after the last treatment, rats were exposed to a 5-min session in the open-field test (OF). Corticosterone and leptin serum levels were determined by ELISA in samples collected within 30 min after the OF. Results showed that rats were hypoactive (decreased rearing, peripheral, and total crossings), and that corticosterone and leptin levels were increased 5 days after alcohol cessation. Four days of NAC prevented the behavioral and biochemical changes brought about by alcohol cessation. We suggest that, in addition to the anti-addictive properties reported for other drugs of abuse, NAC is potentially useful in the management of alcohol withdrawal.

DNA methylation of the LEP gene is associated with craving during alcohol withdrawal

Different studies have described evidence for an association between leptin serum levels and craving in alcohol dependent patients. As leptin expression is regulated by DNA methylation we investigated changes of DNA methylation of the LEP gene promoter region in alcohol dependent patients undergoing withdrawal. Results show that low methylation status is associated with increasing serum leptin levels and elevation of craving for alcohol in the referring patients group. These findings point towards a pathophysiological relevance of changes in DNA methylation of the LEP gene promoter region in alcohol dependence.

Changes in circulating leptin levels during acute stress and associations with craving in abstinent smokers: a preliminary investigation

Recent research suggests a role for the appetite hormone leptin in cigarette smoking. This study examined patterns of change in leptin in response to stress and associations with craving during the initial phase of a quit attempt. Thirty-six smokers (average age±SEM, 33.4±2.4) interested in smoking cessation set a quit day and were required to be abstinent for 24h. After, they completed a laboratory session including public speaking and cognitive challenges, and attended 4 weekly post-cessation assessments. Blood samples and self-report measures were collected throughout the laboratory session. The results indicated that leptin levels significantly increased following exposure to acute stress. We also found positive correlations between leptin and craving for cigarettes. No differences were observed in leptin levels between smokers who maintained abstinence for 4 weeks and those who relapsed during this period. These findings suggest that leptin levels may change in response to stress and that leptin could be a useful marker of craving for smoking.

Leptin influence in craving and relapse of alcoholics and smokers

Leptin inhibits signaling of dopamine in the nucleus accumbens, suggesting its role in regulating stress and its possible involvement in the neurobiology of reward system. The aim of this study was to review of the literature on the influence of leptin in the craving for alcohol and tobacco and whether there is already evidence that leptin may be a biomarker to indicate risk for craving and relapse. The review used as data bases Medline, LILACS and SciElo in the period between 2000 and 2012. Keywords were leptin, substance use disorders, craving and withdrawal, in Portuguese and English. Only 12 articles were met the inclusion criteria, relating leptin with craving in alcoholics (n = 10) and smokers (n = 2). No studies were found in the LILACS database. Leptin levels increase during abstinence and this may be related to a reduction of dopaminergic action in mesolimbic system, resulting in a greater intensity of craving and maintenance of addictive behavior. Although there are few studies, the most recent results indicate the usefulness of leptin as a marker of risk for relapse among smokers and alcoholics in abstinence.

Association of V89L SRD5A2 polymorphism with craving and serum leptin levels in male alcohol addicts

RATIONALE

A causal role of sex hormones in the onset and course of alcohol dependence is well established. We recently demonstrated that the genetics of the androgen receptor and aromatase relate to craving in alcohol addicts during withdrawal. This relationship involves the modulation of leptin, which affects the mesolimbic dopamine reward circuit. The steroid 5-α reductase 2 (SRD5A2) converts testosterone to dihydrotestosterone and thereby causes increased androgenic potency.

OBJECTIVES

In this study, we explored whether functionally relevant genetic polymorphisms in SRD5A2 (V89L, A49T, [TA](n)) are linked to alcohol addiction and craving.

METHODS AND RESULTS

We investigated 118 male alcohol-addicted inpatients admitted for withdrawal treatment and compared them to 50 healthy age- and body mass index-matched controls. The two groups did not differ in their allelic distributions. Subsequent analyses revealed an association between the V89L genotype and alcohol craving within the patient group (p < 0.05). Leptin accounted for 55 % of this relationship. Compared to VL and VV carriers, LL carriers had reduced serum leptin levels (p < 0.05) and lower levels of craving (p < 0.01). Furthermore, we observed an interaction between the V89L and the TTTAn aromatase polymorphisms (p < 0.05). No effects were found for A49T or (TA)(n).

CONCLUSIONS

These findings further support a crucial role of sex hormone biosynthetic genes and signaling in alcohol withdrawal. Craving is an accepted risk factor for alcohol relapse. Hence, these results might be helpful in predicting the outcomes of alcohol addicts after detoxification. With SRD5A2 inhibitors already in clinical use worldwide, this study may also guide future preventive and therapeutic strategies.

The relationship of appetitive, reproductive and posterior pituitary hormones to alcoholism and craving in humans

A significant challenge for understanding alcoholism lies in discovering why some, but not other individuals, become dependent on alcohol. Genetic, environmental, cultural, developmental, and neurobiological influences are recognized as essential factors underlying a person's risk for becoming alcohol dependent (AD); however, the neurobiological processes that trigger this vulnerability are still poorly understood. Hormones are important in the regulation of many functions and several hormones are strongly associated with alcohol use. While medical consequences are important, the primary focus of this review is on the underlying confluence of appetitive/feeding, reproductive and posterior pituitary hormones associated with distinct phases of alcoholism or assessed by alcohol craving in humans. While these hormones are of diverse origin, the involvement with alcoholism by these hormone systems is unmistakable, and demonstrates the complexity of interactions with alcohol and the difficulty of successfully pursuing effective treatments. Whether alcohol associated changes in the activity of certain hormones are the result of alcohol use or are the result of an underlying predisposition for alcoholism, or a combination of both, is currently of great scientific interest. The evidence we present in this review suggests that appetitive hormones may be markers as they appear involved in alcohol dependence and craving, that reproductive hormones provide an example of the consequences of drinking and are affected by alcohol, and that posterior pituitary hormones have potential for being targets for treatment. A better understanding of the nature of these associations may contribute to diagnosing and more comprehensively treating alcoholism. Pharmacotherapies that take advantage of our new understanding of hormones, their receptors, or their potential relationship to craving may shed light on the treatment of this disorder.

The loss of metabolic control on alcohol drinking in heavy drinking alcohol-dependent subjects

Background

Most physiological studies interested in alcohol-dependence examined ethanol as a pharmacological agent rather than a nutrient. We conducted two studies, which assessed the metabolic and endocrine factors involved in the regulation of alcohol and nutrient intake in alcohol-dependent (AD) subjects. We also examined the potential role of a disruption in energy balance in alcohol-dependence.

Methods and Results

In Study-1, quantitative dietetic interviews of eating and drinking habits were conducted with 97 AD subjects. The population was split around a median alcohol intake value of 12.5 kcal/kg/day. The results showed that the “low alcohol” drinking AD subjects had high Body Mass Index (BMI) and Fat Mass (FM) and alcohol intake was compensated for by a decrease in non-alcoholic intakes. “High alcohol” drinking AD subjects, on the other hand, had low BMI and FM and the total caloric intakes were largely above norms. In Study-2, 24 AD inpatients were submitted to dietetic interviews, calorimetry and blood samplings for the measurement of biomarkers of the regulation of metabolism and satiety, on day 2, 5 and 16 of abstinence. These patients were compared with 20 controls matched for age and gender. We observed in AD patients an increase in cortisol, leptin and PYY plasma levels and a decrease in ghrelin, which might explain the observed decrease in non-alcoholic intakes. However, alcoholic and non-alcoholic intakes correlated positively with basal metabolism and negatively with leptin and leptin/BMI.

Conclusion

For individuals consuming below12.5 kcal/kg/day of alcohol, alcohol intake is compensated for by a decrease in non-alcoholic nutrient intakes, probably due to changes in metabolic and satiety factors. For individuals consuming above 12.5 kcal/kg/day of alcohol, alcohol accelerates metabolism and decreases fat mass and leptin levels, and the total caloric intake largely exceeds norms. A dual model for regulation of energy intake in AD subjects is proposed.

The association between depression and leptin is mediated by adiposity

OBJECTIVE

Animal models suggest that impaired leptin production, or leptin resistance despite increased leptin levels, may contribute to depression. The link between leptin and depression could be mediated by obesity, which is more common in depression and increases leptin production.

METHODS

We administered the Beck Depression Inventory-II (BDI-II) to 537 participants (mean [standard deviation (SD)] age = 51 [9] years; female, 61%) enrolled in the Morehouse and Emory Team up to Eliminate Health Disparities (META-Health) study. Leptin levels were examined as continuous log-transformed values.

RESULTS

Participants with moderate to severe depression had higher levels of leptin (median [interquartile range] 37.7 [17.6-64.9] ng/mL) than those with mild depression (22.9 [7.0-57.9] ng/mL) or minimal to no depression (19.8 ng/mL [7.8-39.1], p = .003). Participants with moderate to severe depression had higher body mass index (BMI) than those with mild or minimal depression (mean [SD] = 33 [8] versus 31 [9] versus 29 [7] kg/m(2), p = .001). After multivariate adjustment for age, sex, race, smoking status, hypertension, diabetes, blood pressure, lipids, and C-reactive protein, the BDI-II score remained a significant predictor of leptin levels (β = 0.093, p = .01). Further adjustment for BMI eliminated the association between the BDI-II score and leptin (β = 0.03, p = .3). Adjusting for waist circumference in place of BMI revealed similar findings.

CONCLUSIONS

The association between depression and leptin seems to be mediated by increased adiposity in depressed individuals.

Biological mechanisms in alcohol dependence--new perspectives

Neurobiological research in alcohol dependence has led to a new understanding of this addictive disease. While some important mechanisms like alterations in the mesolimbic reward system or changes in the hypothalamus-pituitary-adrenocortical axis have been well studied, other possible neurobiological mechanisms are still unrevealed. This applies for the role of specific neuroendocrinological pathways like the appetite-regulating system and the modification of gene expression, particularly the influence of genetic variants of transcription factors or epigenetic mechanism like DNA methylation or histone acetylation. This review describes the current knowledge regarding these factors, focusing particularly on the role of appetite- and volume-regulating hormones, the role of genetic variants of specific transcription factors and the function of epigenetic alterations in the genomic sequence of candidate genes for alcohol dependence. A further understanding of the influence of transcription factors and epigenetic regulation may help to elucidate the pathophysiological mechanisms in the neurobiology of alcohol dependence.

Sex hormone activity in alcohol addiction: integrating organizational and activational effects

There are well-known sex differences in the epidemiology and etiopathology of alcohol dependence. Male gender is a crucial risk factor for the onset of alcohol addiction. A directly modifying role of testosterone in alcohol addiction-related behavior is well established. Sex hormones exert both permanent (organizational) and transient (activational) effects on the human brain. The sensitive period for these effects lasts throughout life. In this article, we present a novel early sex hormone activity model of alcohol addiction. We propose that early exposure to sex hormones triggers structural (organizational) neuroadaptations. These neuroadaptations affect cellular and behavioral responses to adult sex hormones, sensitize the brain's reward system to the reinforcing properties of alcohol and modulate alcohol addictive behavior later in life. This review outlines clinical findings related to the early sex hormone activity model of alcohol addiction (handedness, the second-to-fourth-finger length ratio, and the androgen receptor and aromatase) and includes clinical and preclinical literature regarding the activational effects of sex hormones in alcohol drinking behavior. Furthermore, we discuss the role of the hypothalamic-pituitary-adrenal and -gonadal axes and the opioid system in mediating the relationship between sex hormone activity and alcohol dependence. We conclude that a combination of exposure to sex hormones in utero and during early development contributes to the risk of alcohol addiction later in life. The early sex hormone activity model of alcohol addiction may prove to be a valuable tool in the development of preventive and therapeutic strategies.

Leptin as a neuroactive agent

OBJECTIVE

To review the literature regarding the role of leptin in psychiatric disorders.

METHODS

A PubMed search was undertaken using the following keywords: leptin, psychosis, affective disorders, alcohol, psychiatry, depression, dementia, and eating disorders. The articles were restricted to the English language.

RESULTS

The role of leptin in psychiatric populations has been the subject of increasing investigation. Basic science and clinical observations support a role for leptin in mediating cognition and reward processes. The role of leptin in psychiatric illnesses characterized by cognitive deficits has gained increased attention in recent years. Leptin deficiency and resistance have also been associated with eating disorders as well as affective, alcohol dependence, and psychotic disorders. The mechanisms underlining these associations remain to be determined.

CONCLUSIONS

Clinical research suggests an important role of leptin in psychiatric illnesses. Given the morbidity associated with mental illness, clinical research on the role of leptin and related novel therapeutic modalities is needed.

Mood disorders and obesity: understanding inflammation as a pathophysiological nexus

The aim of this review is to evaluate the evidentiary base supporting the hypothesis that the increased hazard for obesity in mood disorder populations (and vice versa) is a consequence of shared pathophysiological pathways. We conducted a PubMed search of all English-language articles with the following search terms: obesity, inflammation, hypothalamic-pituitary-adrenal axis, insulin, cognition, CNS, and neurotransmitters, cross-referenced with major depressive disorder and bipolar disorder. The frequent co-occurrence of mood disorders and obesity may be characterized by interconnected pathophysiology. Both conditions are marked by structural and functional abnormalities in multiple cortical and subcortical brain regions that subserve cognitive and/or affective processing. Abnormalities in several interacting biological networks (e.g. immuno-inflammatory, insulin signaling, and counterregulatory hormones) contribute to the co-occurence of mood disorders and obesity. Unequivocal evidence now indicates that obesity and mood disorders are chronic low-grade pro-inflammatory states that result in a gradual accumulation of allostatic load. Abnormalities in key effector proteins of the pro-inflammatory cascade include, but are not limited to, cytokines/adipokines such as adiponectin, leptin, and resistin as well as tumor necrosis factor alpha and interleukin-6. Taken together, the bidirectional relationship between obesity and mood disorders may represent an exophenotypic manifestation of aberrant neural and inflammatory networks. The clinical implications of these observations are that, practitioners should screen individuals with obesity for the presence of clinically significant depressive symptoms (and vice versa). This clinical recommendation is amplified in individuals presenting with biochemical indicators of insulin resistance and other concurrent conditions associated with abnormal inflammatory signaling (e.g. cardiovascular disease).