Alexander Glahn

Lateral frontal cortex volume reduction in Tourette syndrome revealed by VBM

BackgroundStructural changes have been found predominantly in the frontal cortex and in the striatum in children and adolescents with Gilles de la Tourette syndrome (GTS). The influence of comorbid symptomatology is unclear. Here we sought to address the question of gray matter abnormalities in GTS patients with co-morbid obsessive-compulsive disorder (OCD) and/or attention deficit hyperactivity disorder (ADHD) using voxel-based morphometry (VBM) in twenty-nine adult actually unmedicated GTS patients and twenty-five healthy control subjects.ResultsIn GTS we detected a cluster of decreased gray matter volume in the left inferior frontal gyrus (IFG), but no regions demonstrating volume increases. By comparing subgroups of GTS with comorbid ADHD to the subgroup with comorbid OCD, we found a left-sided amygdalar volume increase.ConclusionsFrom our results it is suggested that the left IFG may constitute a common underlying structural correlate of GTS with co-morbid OCD/ADHD. A volume reduction in this brain region that has been previously identified as a key region in OCD and was associated with the active inhibition of attentional processes may reflect the failure to control behavior. Amygdala volume increase is discussed on the background of a linkage of this structure with ADHD symptomatology. Correlations with clinical data revealed gray matter volume changes in specific brain areas that have been described in these conditions each.

Alcohol-Induced Changes in Methylation Status of Individual CpG Sites, and Serum Levels of Vasopressin and Atrial Natriuretic Peptide in Alcohol-Dependent Patients during Detoxification Treatment

Disturbances of volume-regulating peptides like vasopressin (AVP) and atrial natriuretic peptide (ANP) have been described in early abstinent alcohol-dependent patients. In a longitudinal approach, we investigated whether changes in AVP and ANP serum levels correlated to cytosine-phosphatidyl-guanine (CpG) methylation of the respective gene promoters on days 1, 7 and 14 of alcohol withdrawal. We analyzed the blood samples of 99 patients suffering from alcohol dependence alongside age- and BMI-matched controls. Concerning AVP promoter methylation, we observed an interaction between time of measurement and CpG loci with CpG 2 showing a significant increase in methylation from day 1 to 14. Serum levels of AVP were significantly decreased in the patient group. Compared to healthy controls, promoter-related DNA methylation of the ANP promoter was significantly reduced on days 7 and 14. Moreover, we detected a significant interaction between CpG position and group. In both cases the difference was mainly observed at CpG 1. The present study shows significant changes in the methylation status of individual CpG sites of AVP and ANP. Observing respective alterations of AVP serum protein levels in alcohol-dependent patients during detoxification treatment, we consider methylation as a possible mode of regulation for these proteins during alcohol detoxification.

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.

Atrial natriuretic peptide, arginine vasopressin peptide and cortisol serum levels in opiate-dependent patients.

Preclinical studies suggest that chronic drug abuse profoundly alters stress-responsive systems. The best studied of the stress-responsive systems in humans is the hypothalamic-pituitary-adrenal (HPA) axis. Apart from cortisol, arginine vasopressin peptide (AVP), and atrial natriuretic peptide (ANP) are known to directly impact upon the HPA axis in addictive behavior. We investigated alterations in ANP, AVP and cortisol serum levels in opiate-dependent patients who received diacetylmorphine treatment within a structured opiate maintenance program. ANP serum levels were significantly increased in opiate-dependent patients as compared to healthy controls, whereas AVP and cortisol serum levels were reduced. The ANP, AVP and cortisol serum levels were not significantly associated with the psychometric dimensions of heroin craving. In conclusion, chronic drug abuse profoundly alters stress-responsive systems like the HPA axis. Alterations of AVP, ANP and cortisol appear to constitute an important component in the neurobiology of opiate-dependent patients.

Promoter Polymorphism rs886205 Genotype Interacts With DNA Methylation of the ALDH2 Regulatory Region in Alcohol Dependence

Aims Aldehyde dehydrogenase 2 (ALDH2) protects cells from ethanol toxicity by metabolizing acetaldehyde. We studied the single nucleotide polymorphism (SNP) rs886205s located between a negative and a positive regulating promoter element in the ALDH2 gene. The negative regulatory region was already associated with differential DNA methylation in the two allele variations of rs886205 SNP. Another CpG island, in the positive regulatory region of the ALDH2 promoter, extends through the SNP rs886205 and a nuclear receptor response element. Methods We assessed rs886305 genotype and DNA methylation using bisulfite sequencing in a cohort of 83 male alcohol-dependent patients undergoing detoxification treatment (Days 1, 7 and 14) and in 33 male age-matched controls. Luciferase reporter assays were performed to address the functional significance of genotype and methylation. Results We observed a higher methylation in alcohol-dependent patients compared to controls. Patients with AA (n = 52) or GG/GA (n = 31) genotype differed significantly in baseline methylation levels as well as in methylation kinetics during withdrawal. AA carriers display an increase in methylation from low baseline levels while GG/GA showed the inverse pattern. The reporter gene assays corroborate these data by showing a significant effect of genotype on ALDH2 expression as well as an interaction between genotype and methylation. Conclusion Our results describe a new regulatory role of rs886205 in the methylation of ALDH2 promoter region and provide additional insight into the complex regulation of ALDH2 under the condition of alcohol dependence. Short summary Genetic variations have been described to influence DNA promoter methylation of various genes. We investigated the association between the polymorphism rs886205, located on ALDH2 promoter and methylation kinetics of the neighboring CpG island in alcohol-dependent patients. Luciferase reporter assays showed functional significance of genotype, methylation and a genotype-epigenotype interaction in vitro.

Impaired Regulation of ALDH2 Protein Expression Revealing a Yet Unknown Epigenetic Impact of rs886205 on Specific Methylation of a Negative Regulatory Promoter Region in Alcohol-Dependent Patients.

Acetaldehyde, the carcinogenic metabolite of ethanol known to provoke aversive symptoms of alcohol consumption, is predominantly eliminated by aldehyde dehydrogenase 2 (ALDH2). Reduced ALDH2 activity correlates with low alcohol tolerance and low risk for alcohol dependence. The ALDH2 promoter polymorphism rs886205 (A>G) is associated with decreased promoter activity, but a molecular mechanism and allele-dependent ALDH2 protein expression has not been described yet. On the basis of allele-dependent epigenetic effects, we analyzed the rs886205 genotype, methylation rates of cytosine-phosphatidyl-guanine (CpG)-sites within a regulatory promoter region and ALDH2 protein levels in 82 alcohol-dependent patients during a 2-week withdrawal and compared them to 34 matched controls. Patients without the G-allele of rs886205 showed higher methylation of the promoter region than controls and readily adapted epigenetically as well as on protein level during withdrawal, while patients with the G-allele displayed retarded methylation readjustment and no change in ALDH2 protein levels. Our data provide novel insights into an unknown genetic-epigenetic interaction, revealing impaired ALDH2 protein expression in patients with the G-allele of rs886205. Additionally, we checked for an association between rs886205 and protection against alcohol dependence and found a trend association between the G-allele and protection against alcohol dependence that needs replication in a larger Caucasian cohort.

No association between the ALDH2 promoter polymorphism rs886205, alcohol dependence, and risky alcohol consumption in a German population

Department of Psychiatry, Socialpsychiatry and Psychotherapy, Center for Addiction Research (CARe), Molecular Neurosciences Laboratory, Department of Psychiatry, Socialpsychiatry and Psychotherapy, Hannover Medical School, Hannover, Department of Addiction and Psychotherapy, LVR-Clinic Bonn, Bonn, Department of Psychiatry and Psychotherapy, University Hospital, FriedrichAlexander University of Erlangen-Nuremberg, Erlangen, Research Unit of Molecular Epidemiology, Institute of Genetic Epidemiology, Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Epidemiology II, Helmholtz Center Munich, German Center for Diabetes Research, Neuherberg, Department of Genetic Epidemiology, Institute of Medical Informatics, Biometry and Epidemiology, Ludwig-Maximilians Universität, Munich, Germany and Department of Neurology, University Hospital Zürich, Zürich, Switzerland

Smoking and Promoter-Specific Deoxyribonucleic Acid Methylation of the Atrial Natriuretic Peptide Gene: Methylation of Smokers and Non-Smokers Differs Significantly during Withdrawal

Background: Atrial natriuretic peptide (ANP) is well known in psychiatric disorders to modulate hypothalamic-pituitary-adrenal axis activity. Disturbances of ANP have been described in early abstinent alcohol-dependent patients. This is the first longitudinal investigation on cytosine-phosphatidyl-guanine (CpG)-island promoter methylation of the ANP gene in the blood of tobacco-dependent patients. Methods: In a longitudinal approach, we investigated whether changes in ANP serum levels correlated to CpG methylation of the respective gene promoters on days 1, 7, and 14 of tobacco withdrawal. Results and Conclusion: Compared to non-smokers, promoter-related deoxyribonucleic acid methylation of the ANP promoter was significantly elevated on days 7 and 14 of withdrawal in tobacco-dependent patients. Baseline methylation status of the ANP promoter was not significantly different from controls, arguing for an impaired regulation during withdrawal.

The Epigenetic Regulation of GATA4-Dependent Brain Natriuretic Peptide Expression during Alcohol Withdrawal.

Objective: Natriuretic peptides participate in the collection of metabolic effects during alcohol withdrawal. Having witnessed modulation of other natriuretic peptides in alcohol-dependent patients during alcohol withdrawal, we were interested in the relation of brain natriuretic peptide (BNP) methylation with protein expression and craving in this longitudinal study. Methods: Ninety-nine male patients were compared to 101 healthy controls concerning epigenetic regulation and protein expression during detoxification treatment. Results: With BNP expression being GATA4 dependent, we observed a correlation of GATA4 binding site methylation and protein expression. BNP serum levels and Obsessive Compulsive Drinking Scale scores are significantly decreased during withdrawal. Focusing on the two CpGs that are between GATA transcription factor binding sites, statistical analysis revealed a reversely proportional methylation pattern, significantly increasing with ongoing detoxification and thereby supporting the observed serum level changes. Conclusion: Without the functional knowledge about regulation of BNP expression via the GATA transcription factor, it would have been easy to take the mean results of the global CpG data and propose a direct relationship between methylation and expression. Thus, these findings are a voice for functionally and mechanistically approved results. There was no causal relationship between protein expression levels and epigenetic changes. Further research is needed which includes protein expression and other approaches.

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 leptins 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.