Methylation of the Oxytocin, Oxytocin Receptor, and Vasopressin Gene Promoters in Tobacco Use Disorder during Cessation.

INTRODUCTION: Vasopressin (AVP) and oxytocin (OT) exert sex-specific effects on social pair bonding and stress reactions while also influencing craving in substance use disorders. In this regard, intranasal oxytocin (OT) and AVP antagonists present potential treatments for tobacco use disorder (TUD). Since transcription of both hormones is also regulated by gene methylation, we hypothesized sex-specific changes in methylation levels of the AVP, OT, and OT receptor (OXTR) gene during nicotine withdrawal. METHODS: The study population consisted of 49 smokers (29 males, 20 females) and 51 healthy non-smokers (25 males, 26 females). Blood was drawn at day 1, day 7, and day 14 of smoking cessation. Craving was assessed with the questionnaire on smoking urges (QSU). RESULTS: Throughout cessation, mean methylation of the OT promoter gene increased in males and decreased in females. OXTR receptor methylation decreased in females, while in males it was significantly lower at day 7. Regarding the AVP promoter, mean methylation increased in males while there were no changes in females. Using mixed linear modeling, CpG position, time point, sex, and the interaction of time point and sex as well as time point, sex, and QSU had a significant fixed effect on OT and AVP gene methylation. The interaction effect suggests that sex, time point, and QSU are interrelated, meaning that, depending on the sex, methylation could be different at different time points and vice versa. There was no significant effect of QSU on mean OXTR methylation. DISCUSSION: We identified differences at specific CpGs between controls and smokers in OT and AVP and in overall methylation of the AVP gene. Furthermore, we found sex-specific changes in mean methylation levels of the mentioned genes throughout smoking cessation, underlining the relevance of sex in the OT and vasopressin system. This is the first study on epigenetic regulation of the OT promoter in TUD. Our results have implications for research on the utility of the AVP and OT system for treating substance craving. Future studies on both targets need to analyze their effect in the context of sex, social factors, and gene regulation.

Therapeutic Use of Cannabinoids in Critically Ill Patients: A Survey of Intensive Care Physicians in Germany.

Background: In the course of the legalization of cannabis for therapeutic purposes in Germany, there has been growing interest in the medical use of cannabinoids. To date, the therapeutic potential of cannabinoids for the treatment of critically ill patients has not been explored. Objectives: This study aims to understand better whether and how frequently cannabinoids have been administered to critically ill patients in recent years. Study Design: Initially, a survey was conducted among physicians working in intensive care units (ICUs) at the Hannover Medical School. Subsequently, 653 physicians working in ICUs throughout Germany were surveyed. The frequency and regimen of cannabinoid therapy initiated by the participating physicians in the last 2 years at the time of the survey were characterized. Results: Eight out of 9 physicians at Hannover Medical School and 59 out of 653 physicians in ICUs in Germany participated. At Hannover Medical School, 6 out of 8 physicians and in ICUs in Germany, 16 out of 59 physicians had used cannabinoids in some patients (mainly 9-10) during the 2-year period studied, with dronabinol in doses between 1 and 20 mg being their cannabinoid of choice. Metabolic and psychological distress and medication savings, followed by pain and nausea/vomiting, were the most frequently cited indications for cannabinoid therapy. No relevant safety issues arrived. Lack of personal experience, limited evidence, and gaps in knowledge were the most commonly cited reservations about cannabinoid use. Conclusions: During a 2-year period, dronabinol is used in a few critically ill patients in ICUs. The main indications are to reduce metabolic and psychological distress and to save medication. The majority of participating physicians indicated that the use of cannabinoids in the context of critical care medicine needs further exploration.

Cytosine methylation in GABA B1 receptor identifies alcohol-related changes for men in blood and brain tissues.

AIMS: Alcohol use alters the reward signaling processes contributing to the development of addiction. We studied the effects of alcohol use disorder (AUD) on brain regions and blood of deceased women and men to examine sex-dependent differences in epigenetic changes associated with AUD. We investigated the effects of alcohol use on the gene promoter methylation of GABBR1 coding for GABAB receptor subunit 1 in blood and brain. METHODS: We chose six brain regions associated with addiction and the reward pathway (nucleus arcuatus, nucleus accumbens, the mamillary bodies, amygdala, hippocampus and anterior temporal cortex) and performed epigenetic profiling of the proximal promoter of the GABBR1 gene of post-mortem brain and blood samples of 17 individuals with AUD pathology (4 female, 13 male) and 31 healthy controls (10 female, 21 male). RESULTS: Our results show sex-specific effects of AUD on GABBR1 promoter methylation. Especially, CpG -4 showed significant tissue-independent changes and significantly decreased methylation levels for the AUD group in the amygdala and the mammillary bodies of men. We saw prominent and consistent change in CpG-4 across all investigated tissues. For women, no significant loci were observed. CONCLUSION: We found sex-dependent differences in GABBR1 promoter methylation in relation to AUD. CpG-4 hypomethylation in male individuals with AUD is consistent for most brain regions. Blood shows similar results without reaching significance, potentially serving as a peripheral marker for addiction-associated neuronal adaptations. Further research is needed to discover more contributing factors in the pathological alterations of alcohol addiction to offer sex-specific biomarkers and treatment.

Comparing DRD2 Promoter Methylation Between Blood and Brain in Alcohol Dependence.

AIMS: The dopamine receptor D2 (DRD2) is substantially involved in several forms of addiction. In addition to genetic polymorphisms, epigenetic mechanisms have emerged as an important means of regulation. Previously, DRD2 hypo- and hyper-methylation have been observed in alcohol use disorder (AUD). Blood samples are commonly used as a surrogate marker of epigenetic alterations in epigenetic research, but few specific comparisons between blood and brain tissue samples in AUD exist. METHODS: We used post-mortem brain tissue samples of 17 deceased patients with AUD and 31 deceased controls to investigate the relationship between blood and brain methylation of the DRD2 promoter. RESULTS: When investigating individual cytosine methylation sites (CpG), several significant differences were found in the nucleus accumbens and hippocampus in the study population. Investigating binding sites with significant differences in methylation levels revealed hypomethylated CpGs targeting mainly activating transcription factors. CONCLUSION: These findings support an altered transcription of the DRD2 gene in AUD specimens with a consecutively changed reward response in the brain. While methylation between specific brain regions and blood is comparable, our study further suggests that blood methylation cannot provide meaningful perspectives on DRD2 promoter methylation in the brain.

Chronic Voluntary Alcohol Consumption Alters Promoter Methylation and Expression of Fgf-2 and Fgfr1.

Alcohol abuse accounts for 3.3 million deaths annually, rendering it a global health issue. Recently, fibroblast growth factor 2 (FGF-2) and its target, fibroblast growth factor receptor 1 (FGFR1), were discovered to positively regulate alcohol-drinking behaviors in mice. We tested whether alcohol intake and withdrawal alter DNA methylation of Fgf-2 and Fgfr1 and if there is a correlation regarding mRNA expression of these genes. Blood and brain tissues of mice receiving alcohol intermittently over a six-week period were analyzed using direct bisulfite sequencing and qRT-PCR analysis. Assessment of Fgf-2 and Fgfr1 promoter methylation revealed changes in the methylation of cytosines in the alcohol group compared with the control group. Moreover, we showed that the altered cytosines coincided with binding motives of several transcription factors. We also found that Fgf-2 and Fgfr1 gene expression was significantly decreased in alcohol-receiving mice compared with control littermates, and that this effect was specifically detected in the dorsomedial striatum, a brain region involved in the circuitry of the reward system. Overall, our data showed alcohol-induced alterations in both mRNA expression and methylation pattern of Fgf-2 and Fgfr1. Furthermore, these alterations showed a reward system regional specificity, therefore, resembling potential targets for future pharmacological interventions.

Dysregulated Methylation Patterns in Exon IV of the Brain-Derived Neurotrophic Factor (BDNF) Gene in Nicotine Dependence and Changes in BDNF Plasma Levels During Smoking Cessation.

Introduction: Several studies reported dysregulated protein levels of brain-derived neurotrophic factor (BDNF) in smokers and during cessation. However, the epigenetic regulation of the BDNF gene has not yet been investigated. We measured the plasma levels of BDNF and the epigenetic regulation of exon IV of the BDNF gene in smokers compared to healthy controls over a cessation period of 14 days. Method: We measured BDNF plasma levels and BDNF promoter methylation in 49 smokers and 51 non-smokers at baseline, day 7, and day 14 of smoking cessation. Mean methylation levels of 11 Cytosine Guanosine dinucleotides of exon IV of the BDNF gene were determined via bisulfite sequencing. Results: BDNF plasma and methylation levels were significantly lower in healthy controls when compared with smokers across all time points. BDNF levels for smokers decreased significantly during the cessation period. Comparing the sexes, female smokers showed significantly lower plasma BDNF levels than healthy controls at baseline and over 14 days of cessation. Male and female smokers showed significantly higher mean methylation rates than non-smokers at baseline. In male smokers, mean methylation levels decreased significantly during the cessation period. Conclusion: Our findings replicate the findings of previous studies that BDNF plasma levels are altered in smokers. Furthermore, BDNF expression and gene methylation are altered during the first 14 days of cessation. Our novel findings of dysregulated methylation patterns in exon IV of the BDNF gene further support the thesis that BDNF plays a role in nicotine dependence.

Neurohumoral Profiles and Childhood Adversity of Patients with Multisomatoform Disorder and Pain as the Leading Bodily Symptom.

OBJECTIVE: Patients suffering from chronic pain often present with multifactorial underlying conditions, sometimes without concrete pathological physical findings. Functional somatic syndromes (FSS) and somatoform disorders show a high prevalence of 8-20% and are often associated with adverse childhood experiences (ACE) and chronic stress. As many different FSS have overlapping symptoms, the concept of multisomatoform disorder (MSD) has been introduced as an encompassing concept. We hypothesize that a common neurohumoral profile is present in patients with MSD that is distinct from gender- and age-matched controls and thus provides insight into possible common underlying mechanisms. DESIGN: In 151 patients with MSD (138 females) and 149 matched controls (131 females), we determined ACE by the Childhood Trauma Questionnaire (CTQ) and chronic stress by the Trier Inventory for Chronic Stress (TICS). Furthermore, the serum levels of leptin, FSH, LH, cortisol, DHEA-S, and IGF-1 have been assessed. RESULTS: There were significant differences in the levels of leptin, FSH, IGF-1, and cortisol between patients and controls, mainly driven by female participants. Levels of leptin were significantly correlated with BMI in patients, in controls, and in the female subgroup. This correlation was exaggerated in female patients when compared to female controls. Both CTQ and TICS predicted MSD directly and indirectly through the levels of leptin. CONCLUSION: There is evidence of a distinct neurohumoral profile in female patients with MSD when compared to matched healthy controls, similar to what has been demonstrated in other chronic pain states. The observed profile can be taken as possible evidence for a dysregulated response to chronic stress and metabolic balance as well as a state of hypocortisolism and HPA-axis dysfunction. ACE and chronic stress play a major role in the development of MSD and altered neurohumoral profile.

Leptin promoter methylation in female patients with painful multisomatoform disorder and chronic widespread pain.

BACKGROUND: Different functional somatic syndromes (FSS), fibromyalgia (FMS) and other unexplained painful conditions share many common clinical traits and are characterized by troubling and functionally disabling somatic symptoms. Chronic pain is most frequently reported and at the center of patients' level of disease burden. The construct of multisomatoform disorder (MSD) allows to subsume severely impaired patients suffering from FSS, FMS and other unexplained painful conditions to be examined for common underlying processes. Altered leptin levels and a pathological response of the HPA-axis as a result of chronic stress and childhood trauma have been suggested as one of the driving factors of disease development and severity. Previous studies have demonstrated that methylation of the leptin promoter can play a regulatory role in addiction. In this study, we hypothesized that methylation of the leptin promoter is influenced by the degree of childhood traumatization and differs between patients with MSD and controls. A cohort of 151 patients with MSD and 149 matched healthy volunteers were evaluated using clinical and psychometric assessment while methylation level analysis of the leptin promoter was performed using DNA isolated from whole blood. RESULTS: In female controls, we found CpG C-167 to be negatively correlated with leptin levels, whereas in female patients CpG C-289, C-255, C-193, C-167 and methylation cluster (C-291 to C-167) at putative bindings sites for transcription factors Sp1 and c/EBPalpha were negatively correlated with leptin levels. Methylation levels were significantly lower in female patients CpG C-289 compared with controls. When looking at female patients with chronic widespread pain methylation levels were significantly lower at CpG C-289, C-255 and methylation cluster (C-291 to C-167). CONCLUSION: Our findings support the hypothesis that epigenetic regulation of leptin plays a role in the regulation of leptin levels in patients with MSD. This effect is more pronounced in patients with chronic widespread pain.

Sudden infant death syndrome revisited: serotonin transporter gene, polymorphisms and promoter methylation.

BACKGROUND: Based on findings in the brain stems of SIDS victims, the serotonin transporter (5-HTT) gene has been discussed to be associated with SIDS. METHODS: In the largest study to date, we investigated the promoter length (5-HTTLPR) and intron 2 VNTR polymorphisms in 274 cases and 264 controls and the Ile425Val polymorphism in 65 cases and 64 controls. Moreover, the methylation of the internal promoter region was investigated in 35 cases and 14 controls. RESULTS: For 5-HTTLPR, we observed a trend towards an association of allele L (58.8% vs. 53.4%) with SIDS and significant results were observed after stratifying for age, season at death, and prone position. Nevertheless, when pooling all published data, a significant association of allele L with SIDS is confirmed (p: 0.001). For the intron 2 VNTR polymorphism, no significant differences were observed. After pooling, a significant accumulation of the rare allele 9 was observed in SIDS (2.1% vs. 0.6%; p: 0.018). For the Ile425Val polymorphism, no differences were observed. CONCLUSION: We conclude that genetic variation at this gene might be of some importance in SIDS. Epigenetic analysis of the internal promoter, however, revealed no influence on the relative risk to succumb to SIDS. IMPACT: This is the largest study published up to now on 5-HTT gene polymorphisms and SIDS. Polymorphisms in the 5-HTT gene appear to contribute (although to a small degree) to the risk to die from SIDS. There is no evidence that a methylation of the promoter region is of impact for the etiology of SIDS.

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.

Epigenetic Regulation of Neural Transmission after Cerebellar Fastigial Nucleus Lesions in Juvenile Rats.

Structural and functional abnormalities in the cerebellar midline region, including the fastigial nucleus, have been reported in neuropsychiatric disorders, also comprising the cerebellar cognitive affecting syndrome. In rats, early fastigial lesions reduce social interaction during development and lead to cognitive and emotional deficits in adults, accompanied by compromised neuronal network activity. Since epigenetic mechanisms are implicated in the etiology of neuropsychiatric disorders, we investigated whether fastigial nucleus lesions in juvenile rats would impact epigenetic regulation of neural transmission. The fastigial nucleus was lesioned bilaterally in 23-day-old male rats. Sham-lesion and naïve rats served as controls. DNA methylation was investigated for target genes of the GABAergic, dopaminergic, glutamatergic and oxytocinergic systems in brain regions with anatomic connections to the fastigial nucleus, i.e., medial prefrontal cortex, nucleus accumbens, striatum, thalamus, and sensorimotor cortex. Protein expression was examined for the respective target genes in case of altered DNA methylation between lesion and control groups. Lesioning of the fastigial nucleus led to significant differences in the epigenetic regulation of glutamate decarboxylase 1 and the oxytocin receptor in the nucleus accumbens and the prefrontal cortex. No differences were found for the other target genes and brain regions. Our findings indicate that epigenetic dysregulation after lesioning of the fastigial nucleus may influence long-term recovery and the emergence of behavioral changes. Together with previous behavioral and electrophysiological investigations of this rat model, these observations can play a role in the cerebellar cognitive affective syndrome and other neuropsychiatric disorders.

Trauma Severity in Early Childhood Correlates with Stress and Satiety Hormone Levels in a Pilot Cohort Receiving Diamorphine Maintenance Treatment.

AIMS: Childhood trauma is of importance for the manifestation of substance-related disorders and maintenance of hypothalamic-pituitary-adrenal (HPA)-axis disorders. Since stress plays a crucial role in opioid compliance and craving, we investigated the immediate effects of diacetylmorphine application on the HPA axis. In particular, adrenocorticotropic hormone (ACTH) and cortisol secretion, as well as satiety regulating proopiomelanocortin peptides α-melanocyte-stimulating hormone (MSH) and ß-endorphin (END) in a cohort of opioid-dependent patients in diamorphine maintenance treatment concerning the clinical severity of their childhood trauma. METHODS: We compared the serum levels of ACTH, cortisol, MSH, and END in 15 opioid-dependent patients. All participants received treatment with diamorphine and were observed at 5 timepoints before and after injection. We split the cohort into 2 subgroups concerning childhood trauma measured by the Childhood Trauma Questionnaire. RESULTS: Splitting in 2 subgroups for mild (5) and severe trauma (10), we found that while both groups show a significant reduction of ACTH and cortisol levels over time, slopes display different progressions over time for cortisol (F[1.6] = 9.38, p = 0.02), while remaining identical for ACTH (F[1.6] = 1.69, p = 0.24). Also, levels of both MSH and END were significantly lower in severely traumatized patients. CONCLUSIONS: For the first time, we present a detailed representation of stress- and addiction-related proteins for the first 5 h after diamorphine application, demonstrating the interrelationship between stress hormones and childhood trauma as well as its potential effects on the progression of addictions such as opioid dependence.

Alcohol consumption alters Gdnf promoter methylation and expression in rats.

Alcohol use disorder is one of the most disabling diseases worldwide. Glial-cell derived neurotrophic factor (Gdnf) shows promising results concerning the inhibition of alcohol consumption in rodent models. We investigated the epigenetic regulation of Gdnf following ethanol consumption and withdrawal in a rat model. 32 Wistar rats underwent 7 weeks of intermittent access to alcohol in a 2-bottle choice (IA2BC). Whole blood, Nucleus Accumbens (NAc) and Ventral Tegmental Area (VTA) were collected immediately after the last 24 h of an alcohol-drinking session (alcohol group, AG) or 24 h after withdrawal (withdrawal group, WG). MRNA levels were measured using real-time quantitative PCR. Bisulfite-conversion of DNA and capillary sequencing was used to determine methylation levels of the core promoter (CP) and the negative regulatory element (NRE). The CP of the AG in the NAc was significantly less methylated compared to controls (p < 0.05). In the NAc, mRNA expression was significantly higher in the WG (p < 0.05). In the WG, mRNA expression levels in the VTA were significantly lower (p < 0.05) and showed significantly less methylation in the NRE in the VTA (p < 0.001) and the NAc (p < 0.01) compared to controls. Changes in the cerebral mRNA expression correspond to alterations in DNA methylation of the Gdnf promoter in a rodent model. Our results hold clinical relevance since differences in Gdnf mRNA expression and DNA methylation could be a target for pharmacological interventions.

Fluoxetine induces glucose uptake and modifies glucose transporter palmitoylation in human peripheral blood mononuclear cells.

Introduction: In line with the monoamine hypothesis of major depressive disorder (MDD), the clinical efficacy of the selective serotonin reuptake inhibitor fluoxetine has classically been ascribed to central serotonin enhancing properties. Current research described disturbances in brain energy metabolism in MDD. Additionally, fluoxetine showed beneficial effects in neuropsychiatric disorders associated with central energy imbalance. Areas covered: The effect of in vitro fluoxetine exposure on cellular glucose uptake and cerebral glucose transporter function was assessed in human peripheral blood mononuclear cells (PBMC) and murine neuroblastoma N2a cells. Fluoxetine augmented glucose uptake, measured by utilizing the radionuclide-labled glucose analog [18]F-fluorodeoxyglucose, in PBMC without affecting glucose transporter protein content. Analysis of protein palmitoylation using the acyl-biotinyl exchange method revealed GLUT3 to be palmitoylated in PBMC and N2a cells, while palmitoylation of GLUT1 was detected only in N2a cells. Treatment with fluoxetine significantly increased palmitoylation of GLUT3 in PBMC and strongly induced palmitoylation of GLUT1 in PBMC and N2a cells. Expert opinion: Our findings suggest a novel mechanism exerted by fluoxetine targeting glucose metabolism by regulating glucose transporter palmitoylation. Thus, fluoxetine might evoke its therapeutic effects in neuropsychiatric diseases characterized by disturbances in central energy metabolism at least partly by improving cerebral glucose uptake.

DNA-methylation of the dopamin receptor 2 gene is altered during alcohol withdrawal.

The dopaminergic neurotransmission is known to be of crucial importance in addictive behavior. Epigenetic regulation like methylation of DNA influences the function of dopaminergic transmission. The present study investigated alterations of DNA methylation in the dopamine D2 receptor (DRD2)-gene in patients suffering from alcohol dependence. The study sample consists of 99 alcohol dependent males admitted for alcohol withdrawal treatment and a control group of 33 healthy participants. Blood samples underwent bisulfite sequencing to determine levels of DNA-methylation of the promoter region of the DRD2 gene. Mixed linear modeling was used to test differences between patients and controls, course of methylation during detoxification. While DRD2-gene methylation did not differ significantly between patients and controls, we found a significant increase of DRD2-gene methylation during alcohol withdrawal/early abstinence. Craving, measured with the Obsessive Compulsive Drinking Scale (OCDS), was significantly associated with DRD2-gene methylation. Furthermore, smoking significantly influenced DRD2-gene methylation in both, patients and controls. As in other types of addictive disorders, DRD2-gene methylation is altered during alcohol withdrawal/early abstinence. The findings regarding an association with alcohol craving and tobacco consumption point towards a crucial role of DRD2-gene methylation in the neurobiology of addictive behavior.

Childhood traumatization is associated with differences in TRPA1 promoter methylation in female patients with multisomatoform disorder with pain as the leading bodily symptom.

BACKGROUND: The construct of multisomatoform disorder (MSD) is a common point of reference for patients in different somatic and psychosomatic specialties and therefore useful in studying large well-characterized cohorts of a prototype of a somatoform disorder and in parallel as a functional somatic syndrome (FSS). This disorder is characterized by distressing and functionally disabling somatic symptoms with chronic pain as the most frequent and clinically relevant complaint. Pain is perceived by nociceptive nerve fibers and transferred through the generation of action potentials by different receptor molecules known to determine pain sensitivity in pathophysiological processes. Previous studies have shown that for the transient receptor potential ankyrin 1 (TRPA1), receptor methylation of a particular CpG dinucleotide in the promoter region is inversely associated with both heat pain and pressure pain thresholds. In this study, we hypothesized that TRPA1 promoter methylation regulates pain sensitivity of patients with multisomatoform disorder (MSD). A cohort of 151 patients with MSD and 149 matched healthy volunteers were evaluated using quantitative sensory testing, clinical and psychometric assessment, and methylation analysis using DNA isolated from whole blood. RESULTS: We found CpG -628 to be correlated with mechanical pain threshold and CpG -411 to be correlated with mechanical pain threshold in female volunteers, i.e., higher methylation levels lead to higher pain thresholds. A novel finding is that methylation levels were significantly different between patients with no and severe levels of childhood trauma. CpG methylation also correlated with psychometric assessment of pain and pain levels rated on a visual analog scale. CONCLUSION: Our findings support the hypothesis that epigenetic regulation of TRPA1 plays a role in mechanical pain sensitivities in healthy volunteers. They further provide evidence for the possible influence of childhood traumatic experiences on the epigenetic regulation of TRPA1 in patients with MSD.

Alcohol Withdrawal and Proopiomelanocortin Neuropeptides in an Animal Model of Alcohol Dependence.

BACKGROUND: Alcohol is one of the leading threats to health worldwide. Craving for alcohol makes abstinence a difficult challenge by maintaining alcohol dependence. Many studies suppose the hypothalamic-pituitary-adrenal axis, especially the proopiomelanocortin (POMC)-derived neuropeptides, to mediate craving during withdrawal in alcohol dependence. Evidence is available that the two POMC proteins, α-melanocyte-stimulating hormone (α-MSH) and ß-endorphin (ß-END) are altered by alcohol consumption and influence alcohol consumption, respectively. OBJECTIVES: We investigated the dynamics of α-MSH and ß-END during alcohol withdrawal and the influence of intraperitoneal administration of either α-MSH or ß-END in an established rodent model (Wistar rats) for alcohol dependence. RESULTS: After long-term alcohol self-administration over 12 months and repeated deprivation periods for 3 days, we found a significant decrease in α-MSH levels during withdrawal in rodents (p = 0.006) compared to controls, while ß-END levels remained unchanged. Treatment with intraperitoneally administered α-MSH and ß-END did not affect alcohol drinking behavior after deprivation. CONCLUSION: We demonstrate the effects of alcohol deprivation on α-MSH in alcohol-dependent rodents, which appear to mimic α-MSH alteration found after fasting periods during appetite regulation. Therefore, low α-MSH levels are a possible indicator for craving in alcohol-dependent individuals and hence would be a potential target for anti-craving treatment.

DNA Methylation of the Leptin Gene Promoter is Altered by Chronic Alcohol Exposure in an Animal Model for Alcohol Dependence.

Appetite-regulating peptides, such as leptin, are linked to craving and have been in the focus of alcohol dependence research for years. The objective of our study was to investigate the dynamics of leptin gene promoter methylation during alcohol withdrawal and specific treatment in a rodent (rat) model for alcohol dependence. DNA methylation was measured using direct bisulfite sequencing at 0 h, 24 h, and 6 days of alcohol withdrawal as well as after treatment with alpha-melanocyte-stimulating hormone (alpha-MSH), Beta-Endorphin, or saline. We found significantly lower methylation levels in alcohol-consuming animals compared to alcohol-naïve animals. During 6 days of alcohol deprivation, this difference in methylation vanished. Leptin methylation of the alpha-MSH-treated group and 6 days alcohol-deprived animals was significantly higher than that in saline-treated animals, possibly indicating compensatory effects of the treatment. Our results further expand on previous findings from human studies that explain leptin's role in bridging the gap between alcohol consumption and appetite regulation.

Smoking-induced changes in leptin serum levels and c/EBPalpha-related methylation status of the leptin core promotor during smoking cessation.

Previous studies have provided evidence of an association between serum leptin levels and smoking as well as craving during smoking cessation. As promoter methylation also regulates leptin expression, we investigated the leptin gene promoter region of smokers before and after smoking cessation. Since leptin's core promoter region contains an essential c/EBPalpha transcription binding site, we narrowed our investigation to C-300 (-300 base pairs from the transcription start site) of that binding site. Female smokers showed hypermethylation of C-300 compared to non-smokers. Global methylation status is associated with higher craving and the degree of dependence in female smokers. Serum leptin levels in female smokers were significantly higher than in non-smokers. These findings support previous results and, for the first time, point to a pathophysiological role of c/EBPalpha-related C-300 methylation in tobacco dependence.