Severity of alcohol withdrawal symptoms and the T1128C polymorphism of the neuropeptide Y gene

Meta-Analysis on the Association of Neuropeptide Y rs16139 Variant With the Risk of Alcoholism

Introduction: The neuropeptide-Y (NPY) is involved in the development of alcoholism through NPY receptors. A T>C mutation causes substitution of leucine to proline at codon 7 (L7P; rs16139) in the signal peptide of neuropeptide Y is known to cause a 42% increase in plasma NPY levels. Studies that analyzed the association between NPY rs16139 and alcoholism risk did not demonstrate conclusive evidence for this relationship. The present study aims to evaluate the association between NPY gene rs16139 variant and alcohol dependence. Method: An electronic search of databases including PubMed and Google Scholar was performed to retrieve studies investigating the association between NPY rs16139 and alcoholism. The pooled odds ratio (OR) with 95% confidence interval (CI) was calculated in allelic and dominant genetic models. Sensitivity analyses and publication bias were assessed in our meta-analysis. The meta-analysis was conducted using the MetaGenyo web tool. Result: Significant heterogeneity was observed across studies (p < 0.001). Our results have shown that there is no significant association between NPY rs16139 variant and the risk of alcoholism in allelic (OR = 0.98, 95% CI 0.70-1.38, p = 0.921) and dominant models (OR = 0.98, 95% CI 0.69-1.40, p = 0.919). Begg's funnel plot and Egger's test have not shown publication bias (p = 0.332). Conclusion: To the best of our knowledge, this is the first meta-analysis that evaluates the relationship between the NPY rs16139 polymorphism and the risk of alcoholism. Our large-scale meta-analysis suggests that NPY rs16139 polymorphism is not associated with alcoholism. However, further studies are needed to increase our understanding of the relationship between NPY variants in alcoholism.

Behavioral, neurobiological, and neurochemical mechanisms of ethanol self-administration: A translational review

Alcohol use disorder has multiple characteristics including excessive ethanol consumption, impaired control over drinking behaviors, craving and withdrawal symptoms, compulsive seeking behaviors, and is considered a chronic condition. Relapse is common. Determining the neurobiological targets of ethanol and the adaptations induced by chronic ethanol exposure is critical to understanding the clinical manifestation of alcohol use disorders, the mechanisms underlying the various features of the disorder, and for informing medication development. In the present review, we discuss ethanol's interactions with a variety of neurotransmitter systems, summarizing findings from preclinical and translational studies to highlight recent progress in the field. We then describe animal models of ethanol self-administration, emphasizing the value, limitations, and validity of commonly used models. Lastly, we summarize the behavioral changes induced by chronic ethanol self-administration, with an emphasis on cue-elicited behavior, the role of ethanol-related memories, and the emergence of habitual ethanol seeking behavior.

Risk Locus Identification Ties Alcohol Withdrawal Symptoms to SORCS2

BACKGROUND

Efforts to promote the cessation of harmful alcohol use are hindered by the affective and physiological components of alcohol withdrawal (AW), which can include life-threatening seizures. Although previous studies of AW and relapse have highlighted the detrimental role of stress, little is known about genetic risk factors.

METHODS

We conducted a genome-wide association study of AW symptom count in uniformly assessed subjects with histories of serious AW, followed by additional genotyping in independent AW subjects.

RESULTS

The top association signal for AW severity was in sortilin family neurotrophin receptor gene SORCS2 on chromosome 4 (European American meta-analysis n = 1,478, p = 4.3 × 10-9 ). There were no genome-wide significant findings in African Americans (n = 1,231). Bioinformatic analyses were conducted using publicly available high-throughput transcriptomic and epigenomic data sets, showing that in humans SORCS2 is most highly expressed in the nervous system. The identified SORCS2 risk haplotype is predicted to disrupt a stress hormone-modulated regulatory element that has tissue-specific activity in human hippocampus. We used human neural lineage cells to demonstrate in vitro a causal relationship between stress hormone levels and SORCS2 expression, and show that SORCS2 levels in culture are increased upon ethanol exposure and withdrawal.

CONCLUSIONS

Taken together, these findings indicate that the pathophysiology of withdrawal may involve the effects of stress hormones on neurotrophic factor signaling. Further investigation of these pathways could produce new approaches to managing the aversive consequences of abrupt alcohol cessation.

Neuropeptide Y in Alcohol Addiction and Affective Disorders

Neuropeptide Y (NPY), a neuropeptide highly conserved throughout evolution, is present at high levels in the central nervous system (CNS), as well as in peripheral tissues such as the gut and cardiovascular system. The peptide exerts its effects via multiple receptor subtypes, all belonging to the G-protein-coupled receptor superfamily. Of these subtypes, the Y1 and the Y2 are the most thoroughly characterized, followed by the Y5 subtype. NPY and its receptors have been shown to be of importance in central regulation of events underlying, for example, affective disorders, drug/alcohol use disorders, and energy homeostasis. Furthermore, within the CNS, NPY also affects sleep regulation and circadian rhythm, memory function, tissue growth, and plasticity. The potential roles of NPY in the etiology and pathophysiology of mood and anxiety disorders, as well as alcohol use disorders, have been extensively studied. This focus was prompted by early indications for an involvement of NPY in acute responses to stress, and, later, also data pointing to a role in alterations within the CNS during chronic, or repeated, exposure to adverse events. These functions of NPY, in addition to the peptide's regulation of disease states, suggest that modulation of the activity of the NPY system via receptor agonists/antagonists may be a putative treatment mechanism in affective disorders as well as alcohol use disorders. In this review, we present an overview of findings with regard to the NPY system in relation to anxiety and stress, acute as well as chronic; furthermore we discuss post-traumatic stress disorder and, in part depression. In addition, we summarize findings on alcohol use disorders and related behaviors. Finally, we briefly touch upon genetic as well as epigenetic mechanisms that may be of importance for NPY function and regulation. In conclusion, we suggest that modulation of NPY-ergic activity within the CNS, via ligands aimed at different receptor subtypes, may be attractive targets for treatment development for affective disorders, as well as for alcohol use disorders.

Genetic Variation in the Vesicular Monoamine Transporter 1 (VMAT1/SLC18A1) Gene and Alcohol Withdrawal Severity

BACKGROUND

Alcohol withdrawal (AW) can be a serious consequence of alcohol dependence and consists of various neurochemical adaptations in the brain. One such neuroadaptation occurs in the monoamine neurotransmitter system. Recently, a functional variant in the presynaptic vesicular monoamine transporter gene (VMAT1/SLC18A1-Thr136Ile-rs1390938) was found to significantly increase transport of monoamines into synaptic vesicles in vitro. We hypothesize that the alteration of magnitude of monoamine release contributes to severity of AW symptoms.

METHODS

Alcohol-dependent individuals (n = 609; European American n = 340; African American n = 216; other n = 53) were administered the Clinical Institute Withdrawal Assessment of Alcohol Scale, Revised (CIWA-Ar) questionnaire at the time of inpatient admission. Patients were subsequently genotyped for 12 single nucleotide polymorphism (SNP) markers in VMAT1. Association analyses were conducted on the combined sample and separated by ethnicity.

RESULTS

Single marker association tests revealed a significant association between 3 VMAT1 markers and CIWA-Ar scores in the EA sample. The minor alleles of rs1390938 (A) and rs952859 (C) were significantly associated with lower CIWA-Ar scores (p = 0.0006; p = 0.0007), whereas the minor allele of rs3779672 (G) was significantly associated with higher scores (p = 0.006). Additionally, these 3 SNPs were found in a haplotype block that was significantly associated with lower CIWA-Ar scores after haplotype analyses were run (p = 0.009).

CONCLUSIONS

This study shows that genetic variants in VMAT1, including the functional SNP rs1390938, contribute to the severity of AW in patients of European descent. Our data show for the first time a role of presynaptic neurotransmitter release in AW severity. This finding could contribute to identifying patients at risk for severe AW and shed light into the pathophysiology of AW and its treatment.

FKBP5 moderates alcohol withdrawal severity: human genetic association and functional validation in knockout mice

Alcohol withdrawal is associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction. The FKBP5 gene codes for a co-chaperone, FK506-binding protein 5, that exerts negative feedback on HPA axis function. This study aimed to examine the effects of single-nucleotide polymorphisms (SNPs) of the FKBP5 gene in humans and the effect of Fkbp5 gene deletion in mice on alcohol withdrawal severity. We genotyped six FKBP5 SNPs (rs3800373, rs9296158, rs3777747, rs9380524, rs1360780, and rs9470080) in 399 alcohol-dependent inpatients with alcohol consumption 48 h before admission and recorded scores from the Clinical Institute Withdrawal Assessment-Alcohol revised (CIWA-Ar). Fkbp5 gene knockout (KO) and wild-type (WT) mice were assessed for alcohol withdrawal using handling-induced convulsions (HICs) following both acute and chronic alcohol exposure. We found the minor alleles of rs3800373 (G), rs9296158 (A), rs1360780 (T), and rs9470080 (T) were significantly associated with lower CIWA-Ar scores whereas the minor alleles of rs3777747 (G) and rs9380524 (A) were associated with higher scores. The haplotype-based analyses also showed an association with alcohol withdrawal severity. Fkbp5 KO mice showed significantly greater HICs during withdrawal from chronic alcohol exposure compared with WT controls. This study is the first to show a genetic effect of FKBP5 on the severity of alcohol withdrawal syndrome. In mice, the absence of the Fkbp5 gene enhances sensitivity to alcohol withdrawal. We suggest that FKBP5 variants may trigger different adaptive changes in HPA axis regulation during alcohol withdrawal with concomitant effects on withdrawal severity.

Hypothesizing dopaminergic genetic antecedents in schizophrenia and substance seeking behavior

The dopamine system has been implicated in both substance use disorder (SUD) and schizophrenia. A recent meta-analysis suggests that A1 allele of the DRD2 gene imposes genetic risk for SUD, especially alcoholism and has been implicated in Reward Deficiency Syndrome (RDS). We hypothesize that dopamine D2 receptor (DRD2) gene Taq1 A2 allele is associated with a subtype of non-SUD schizophrenics and as such may act as a putative protective agent against the development of addiction to alcohol or other drugs of abuse. Schizophrenics with SUD may be carriers of the DRD2 Taq1 A1 allele, and/or other RDS reward polymorphisms and have hypodopaminergic reward function. One plausible mechanism for alcohol seeking in schizophrenics with SUD, based on previous research, may be a deficiency of gamma type endorphins that has been linked to schizophrenic type psychosis. We also propose that alcohol seeking behavior in schizophrenics, may serve as a physiological self-healing process linked to the increased function of the gamma endorphins, thereby reducing abnormal dopaminergic activity at the nucleus accumbens (NAc). These hypotheses warrant further investigation and cautious interpretation. We, therefore, encourage research involving neuroimaging, genome wide association studies (GWAS), and epigenetic investigation into the relationship between neurogenetics and systems biology to unravel the role of dopamine in psychiatric illness and SUD.

Factor Structure of CIWA-Ar in Alcohol Withdrawal

Objective. To identify the underlying factor structure of alcohol withdrawal syndrome, as measured with CIWA-Ar. Methods. Exploratory factor analysis was conducted on the items of CIWA-Ar. On 201 alcohol-dependent male patients seeking treatment for alcohol withdrawal at 36 hours of abstinence. Results. A three-factor solution was obtained that accounted for 68.74% of total variance. First factor had loading from four items (34.34% variance), second factor also had four items (24.25% variance), and the third had two items (10.04% variance). Conclusions. Factor analysis reveals the existence of multidimensionality of alcohol withdrawal as measured with CIWA-Ar and we found three factors that can be named as delirious, autonomic and nonspecific factors.

Polymorphisms of genes in neurotransmitter systems were associated with alcohol use disorders in a Tibetan population

Studies of linkage and association in various ethnic populations have revealed many predisposing genes of multiple neurotransmitter systems for alcohol use disorders (AUD). However, evidence often is contradictory regarding the contribution of most candidate genes to the susceptibility of AUD. We, therefore, performed a case-control study to investigate the possible associations of genes selected from multiple neurotransmitter systems with AUD in a homogeneous Tibetan community population in China. AUD cases (N = 281) with an alcohol use disorder identification test (AUDIT) score ≥10, as well as healthy controls (N = 277) with an AUDIT score ≤5, were recruited. All participants were genotyped for 366 single nucleotide polymorphisms (SNPs) of 34 genes selected from those involved in neurotransmitter systems. Association analyses were performed using PLINK version 1.07 software. Allelic analyses before adjustment for multiple tests showed that 15 polymorphisms within seven genes were associated with AUD (p<0.05). After adjustment for the number of SNPs genotyped within each gene, only the association of a single marker (rs10044881) in HTR4 remained statistically significant. Haplotype analysis for two SNPs in HTR4 (rs17777298 and rs10044881) showed that the haplotype AG was significantly associated with the protective effect for AUD. In conclusion, the present study discovered that the HTR4 gene may play a marked role in the pathogenesis of AUD. In addition, this Tibetan population sample marginally replicated previous evidence regarding the associations of six genes in AUD.

Association between neuropeptide Y gene polymorphisms and alcohol dependence: a case-control study in two independent populations

BACKGROUND

Alcohol dependence is a chronic, progressive neurobiological brain disorder. Previous research reported an inverse association between ethanol drinking and cerebral neuropeptide Y (NPY) levels. There are conflicting results of studies on NPY gene polymorphisms in association with alcohol dependence in humans.

METHODS

To assess the role of the NPY gene in alcohol dependence, we genotyped three polymorphisms--in a sample of 195 subjects from the Kota population (80 alcohol dependence and 115 controls) and 141 subjects from the Badaga population (80 alcohol dependence and 61 controls). Phenotype was defined based on the DSM-IV criteria. Genotyping was performed using sequencing. Association of the NPY gene with alcohol dependence was tested by using logistic regression and haplotype analyses and linkage disequilibrium.

RESULTS

All three polymorphisms were found to be in the Hardy-Weinberg equilibrium in both populations. The results of our study reveal a significant association between G1258A and alcohol dependence in both the Kota and Badaga populations. The linkage disequilibrium between the markers is not strong or significant. Haplotype analysis also did not show significant association between the NPY gene and alcohol dependence.

CONCLUSION

These data support the hypothesis that alcohol dependence is influenced by the NPY G1258A polymorphism in Indian populations.

Central functions of neuropeptide Y in mood and anxiety disorders

INTRODUCTION

Neuropeptide Y (NPY) is a highly conserved neuropeptide belonging to the pancreatic polypeptide family. Its potential role in the etiology and pathophysiology of mood and anxiety disorders has been extensively studied. NPY also has effects on feeding behavior, ethanol intake, sleep regulation, tissue growth and remodeling. Findings from animal studies have delineated the physiological and behavioral effects mediated by specific NPY receptor subtypes, of which Y1 and Y2 are the best understood.

AREAS COVERED

Physiological roles and alterations of the NPYergic system in anxiety disorders, depression, posttraumatic stress disorder (PTSD), alcohol dependence and epilepsy. For each disorder, studies in animal models and human investigations are outlined and discussed, focusing on behavior, neurophysiology, genetics and potential for novel treatment targets.

EXPERT OPINION

The wide implications of NPY in psychiatric disorders such as depression and PTSD make the NPYergic system a promising target for the development of novel therapeutic interventions. These include intranasal NPY administration, currently under study, and the development of agonists and antagonists targeting NPY receptors. Therefore, we are proposing that via this mode of administration, NPY might exert CNS therapeutic actions without untoward systemic effects. Future work will show if this is a feasible approach.

Genetic Association of NPY Gene Polymorphisms with Dampness-Phlegm Pattern in Korean Stroke Patients

Neuropeptide Y (NPY), which is widely expressed in both the central and peripheral nervous systems, has an important role in a variety of biological fields. In this study, we analyzed the distribution of NPY polymorphisms in dampness-phlegm pattern and non-dampness-phlegm pattern in elderly Korean subjects with cerebral infarction (CI). A total of 1.097 subjects (498 normal subjects and 599 CI patients, including 198 with dampness-phlegm pattern and 401 with non-dampness-phlegm pattern) participated in this study. Genotyping for five SNPs (G-1484A, C-1471T, C-399T, A1201G, and C5325T) was conducted by primer extension. The results were statistically analyzed for genetic association of NPY-polymorphisms with normal versus dampness-phlegm pattern or non-dampness-phlegm pattern subjects. Among the five SNPs tested, the T allele of C-399T has a negative association with the dampness-phlegm pattern and is marked by a decrease in serum cholesterol levels. Furthermore, serum cholesterol levels were significantly higher in dampness-phlegm pattern patients than in non-dampness-phlegm pattern patients.In this study, for the first time, the association of NPY polymorphisms with pattern identification (PI) of traditional Korean medicine (TKM) was analyzed in a large CI patient population.

Alcohol withdrawal syndromes in the intensive care unit

This article reviews the pathophysiology, diagnosis, and treatment of alcohol withdrawal syndromes in the intensive care unit as well as the literature on the optimal pharmacologic strategies for treatment of alcohol withdrawal syndromes in the critically ill. Treatment of alcohol withdrawal in the intensive care unit mirrors that of the general acute care wards and detoxification centers. In addition to adequate supportive care, benzodiazepines administered in a symptom-triggered fashion, guided by the Clinical Institute Withdrawal Assessment of Alcohol scale, revised (CIWA-Ar), still seem to be the optimal strategy in the intensive care unit. In cases of benzodiazepine resistance, numerous options are available, including high individual doses of benzodiazepines, barbiturates, and propofol. Intensivists should be familiar with the diagnosis and treatment strategies for alcohol withdrawal syndromes in the intensive care unit.

Interaction of SLC6A4 and DRD2 polymorphisms is associated with a history of delirium tremens

Several genetic polymorphisms have been reported to be associated with alcohol withdrawal seizures (AWS) and delirium tremens (DT). To replicate and further explore these findings, we investigated the effects of 12 previously reported candidate genetic variations in two groups of alcohol-dependent European Americans with a history of withdrawal, which differed according to the presence (n = 112) or absence (n = 92) of AWS and/or DT. Associations of AWS and/or DT with the genomic and clinical characteristics and gene-gene interaction effects were investigated using logistic regression models. None of the polymorphisms were significantly associated with AWS/DT after correction for multiple testing. However, we found a significant interaction effect of the SLC6A4 promoter polymorphism (5-HTTLPR) and DRD2 exon 8 single nucleotide polymorphism rs6276 on AWS and/or DT history (P = 0.009), which became more significant after adjustment for lifetime maximum number of drinks consumed per 24 hours (P < 0.001). Subsequent analysis revealed an even stronger association of the SLC6A4-DRD2 interaction with DT (P < 0.0001), which remained significant after Bonferroni correction. Results reveal decreased likelihood of DT in alcoholics that carry the DRD2 rs6276 G allele and SLC6A4 LL genotype. This study provides the first evidence to implicate the interaction between serotonin and dopamine neurotransmission in the etiology of DT. Replication is necessary to verify this potentially important finding.

The effect of endogenous preproneuropeptide Y leucine 7 to proline 7 polymorphism on growth and apoptosis in primary cultured HUVECs

Neuropeptide Y (NPY) is a universally expressed neuropeptide involved in the regulation of several physiological functions. The rather common leucine7 to proline7 (L7P) polymorphism in the signal peptide of preproNPY is a functional substitution, which changes the processing and release of NPY in cells. The mutation is associated with altered lipid levels and accelerated atherosclerosis in humans. Based on previous studies, we investigated the effect of the Pro7 allele in endothelial cells, which are known to play a role in the development of atherosclerosis. Cell proliferation and apoptosis were studied in primary cultured, genotyped human umbilical vein endothelial cells (HUVECs). Our results indicate that cells with the [p.L7]+[p.P7] genotype seem to have a tendency to be more sensitive to the growth stimulating effect of NPY and less sensitive to the effect of vascular endothelial growth factor compared to cells with the [p.L7]+[p.L7] genotype. Additionally, cells with the [p.L7]+[p.P7] genotype seem to be more sensitive to apoptosis than [p.L7]+[p.L7] cells. We speculate that the L7P substitution in preproNPY might cause a state of cellular pre-senescence, leading to endothelial dysfunction. This might be one reason for the associations of the L7P polymorphism with atherosclerosis and type II diabetes found in clinical studies.

The genetics of deliria

Delirium not induced by alcohol or other psychoactive substance and alcohol withdrawal delirium (or delirium tremens) are both cerebral syndromes with similar presentations and are associated with various adverse outcomes. Recently, interest in identifying genetic predisposing factors that influence the occurrence or the outcome of delirium has become a prominent point of delirium research. We systematically searched published articles concerning genetic associations and the occurrence and outcome of delirium. Of 33 identified articles, six investigated non-alcohol withdrawal delirium, and from those six, five evaluated an association with apolipoprotein E (APOE). One association of APOE genotype with the emergence of delirium and two associations of APOE genotype with the duration of delirium were reported. The remaining 27 identified articles investigated genetic associations with alcohol withdrawal delirium and were mainly related to dopamine. Two studies reported a significant association of alcohol withdrawal delirium with the dopamine transporter gene (SLC6A3) and the dopamine receptor 3 (DRD3). Results are inconclusive, and no hard evidence exists due primarily to insufficiently powered studies and other methodological issues. Prospective studies incorporating systematic and rigorous diagnostic criteria and involving long term follow up are needed to advance understanding of this field.

Neuropeptide Y receptor genes are associated with alcohol dependence, alcohol withdrawal phenotypes, and cocaine dependence

BACKGROUND

Several lines of evidence in both human and animal studies suggest that variation in neuropeptide Y (NPY) or its receptor genes (NPY1R, NPY2R and NPY5R) is associated with alcohol dependence as well as alcohol withdrawal symptoms. Additional studies suggest that cocaine may affect NPY expression.

METHODS

A total of 39 single nucleotide polymorphisms (SNPs) were genotyped across NPY and its 3 receptor genes in a sample of 1,923 subjects from 219 multiplex alcoholic families of European American descent recruited as part of the Collaborative Studies on the Genetics of Alcoholism (COGA) study. Family-based association analysis was performed to test the primary hypothesis that variation in these genes is associated with alcohol dependence. Secondary analyses evaluated whether there was an association of these SNPs with symptoms of alcohol withdrawal, cocaine dependence, or comorbid alcohol and cocaine dependence.

RESULTS

Although variations in NPY itself were not associated with these phenotypes, variations in 2 NPY-receptor genes were. SNPs in NPY2R provided significant evidence of association with alcohol dependence, alcohol withdrawal symptoms, comorbid alcohol and cocaine dependence, and cocaine dependence (all p < 0.03). Haplotype analyses strengthened the evidence for these phenotypes (global 0.0004 < p < 0.005). SNPs in NPY5R demonstrated significant association with alcohol withdrawal characterized by seizures (p < 0.05).

CONCLUSION

These results indicate that sequence variations in NPY receptor genes are associated with alcohol dependence, particularly a severe subtype of alcohol dependence characterized by withdrawal symptoms, comorbid alcohol and cocaine dependence, and cocaine dependence.

Approach to the genetics of alcoholism: A review based on pathophysiology

Alcohol dependence is a common disorder with a heterogenous etiology. The results of family, twin and adoption studies on alcoholism are reviewed. These studies have revealed a heritability of alcoholism of over 50%. After evaluating the results, it was epidemiologically stated that alcoholism is heterogenous complex disorder with a multiple genetic background. Modern molecular genetic techniques allow examining specific genes involved in the pathophysiology of complex diseases such as alcoholism. Strategies for gene identification are introduced to the reader, including family-based and association studies. The susceptibility genes that are in the focus of this article have been chosen because they are known to encode for underlying mechanisms that are linked to the pathophysiology of alcoholism or that are important for the pharmacotherapeutic approaches in the treatment of alcohol dependence. Postulated candidate genes of the metabolism of alcohol and of the involved neurotransmitter systems are introduced. Genetic studies on alcoholism examining the metabolism of alcohol and the dopaminergic, GABAergic, glutamatergic, opioid, cholinergic and serotonergic neurotransmitter systems as well as the neuropeptide Y are presented. The results are critically discussed followed by a discussion of possible consequences.

Multidimensionality of the Alcohol Withdrawal Symptom Checklist: a factor analysis of the Alcohol Withdrawal Symptom Checklist and CIWA-Ar

BACKGROUND

This study evaluated the factor structure of 2 scales for measuring the severity of the alcohol withdrawal syndrome (AWS): a self-rated scale, the Alcohol Withdrawal Symptoms Checklist (AWSC), and an observer-rated scale, the Clinical Institute Withdrawal Assessment-Alcohol, Revised (CIWA-Ar).

METHODS

Alcohol-dependent male inpatients [n=127, age: 43.0+/-9.7 (mean+/-SD) years] were recruited from an inpatient treatment unit. Both measures of AWS were assessed repeatedly during the initial week of sobriety in these patients. An exploratory factor analysis was applied to the data collected on the first study day.

RESULTS

Five independent factors accounted for 64% of total variance in the AWSC: autonomic arousal, depression, nausea and vomiting, alcohol craving, and tension/anxiety. Three items (abdominal pain, hallucinations, confusion) could not be included in the analysis due to insufficient variance. Three dimensions identified for the CIWA-Ar (autonomic arousal, nausea and vomiting, tension/anxiety) were also captured by the ASWC. Total AWSC scores correlated well with total CIWA-Ar scores (r=0.72), supporting validity of the AWSC. Lower correlations between total CIWA-Ar and the 5 factors (r=0.32-0.52) suggested that the CIWA-Ar and AWSC factors had discriminative value.

CONCLUSIONS

Self-rated measures of AWS could play an important role in complementing observer-rated measures in clinical and research settings. In this sample, the AWSC appeared to identify multiple dimensions of AWS with face validity for clinical relevance.

Genetic Polymorphisms Related to Delirium Tremens: A Systematic Review

BACKGROUND

Delirium tremens (DT) is one of the more severe complications of alcohol withdrawal (AW), with a 5 to 10% lifetime risk for alcohol-dependent patients. The 2 most important neurosystems involved in AW are gamma-aminobutyric acid and glutamate. It is unknown whether these neurosystems are involved in the pathophysiology of DT as well. The candidate gene approach in DT could contribute to this knowledge and demonstrate a possible genetic predisposition for DT. The purpose of this study is to give an overview of all studied genetic polymorphisms in the diverse candidate genes related to DT and to summarize what these studies contribute to insights into the pathophysiology of DT.

METHODS

The inclusion criteria for this literature study were articles in English analyzing the association between a genetic polymorphism and DT without other AW syndromes. Studies were identified until February 2006 in MEDLINE and EMBASE databases.

RESULTS

We found 25 studies dealing with 30 polymorphisms, located in 19 different genes. Positive associations were found in 3 different candidate genes involved in the dopamine transmission, 1 gene involved in the glutamate pathway, 1 neuropeptide gene, and 1 cannabinoid gene. Two candidate genes involved in the dopamine transmission, dopamine receptor D3, and solute carrier family 6, were each associated with DT in 2 different study populations. The other 4 positive associations were not replicated in other studies.

CONCLUSIONS

A total of 8 positive associations out of 30 polymorphisms makes a genetic base for DT plausible. Understanding the pathophysiological process of the development of DT has, indeed, been augmented by the reviewed genetic association studies. These studies suggest that the regulation of dopaminergic neurotransmission may play an important role.

DBH*444G/A polymorphism of the dopamine-β-hydroxylase gene is associated with alcoholism but not with severe alcohol withdrawal symptoms

As the enzyme dopamine-beta-hydroxylase (DbetaH) converts dopamine to norepinephrine and both transmitters seem to be involved in the pathology of alcoholism and severe alcohol withdrawal symptoms, the gene encoding DbetaH (DBH) was applied to explore the genetic background of alcoholism and severe withdrawal symptoms. 102 healthy control subjects and 208 alcoholics, including 97 patients with a history of mild withdrawal symptoms, 57 with a history of alcohol withdrawal seizure (AWS) and 82 with a history of delirium tremens (DT) were genotyped for the DBH*444G/A polymorphism revealing a significantly elevated frequency of genotypes carrying the A-allele (p = 0.02; after Bonferroni adjustment for multiple tests) in alcoholics compared to healthy controls. Frequencies of alleles and genotypes of individuals with mild withdrawal symptoms did not differ significantly from those of patients with DT or AWS.

ASSOCIATION OF THE DOPAMINE TRANSPORTER GENE WITH ALCOHOLISM

AIMS

It was investigated whether the allele A9 of the dopamine transporter gene (DAT1; SLC6A3) is associated with alcoholism, delirium tremens (DT), alcohol withdrawal seizures (AWS), or the daily alcohol intake.

METHODS

A group of 102 healthy subjects and 216 alcoholics, including 97 patients with a history of mild withdrawal symptoms, 65 with a history of AWS and 83 with a history of DT were genotyped and personal data were achieved for statistical evaluation in a case-control design.

RESULTS

The frequency of individuals carrying the allele A9 [f(A9+)] was significantly higher (P = 0.01) in the group of alcoholics [f(A9+) = 0.48] compared with healthy controls [f(A9+) = 0.32]. There was no significant association of the allele A9 with severe withdrawal symptoms or the daily amount of alcohol consumed.

CONCLUSIONS

Our results reveal that the allele A9 is strongly associated with alcoholism but not with withdrawal symptoms or daily alcohol intake.

The T1128C polymorphism of neuropeptide Y gene in a chinese population

BACKGROUND

Several papers have shown that the T1128C polymorphism of the neuropeptide Y (NPY) gene was related to certain diseases and disorders. However, the allele frequency of the 1128C showed significant differences among some populations with different genetic backgrounds, being absent in Japanese and Korean populations. Therefore, this present study was aimed to explore whether the T1128C polymorphism of the NPY gene exists in a Chinese population.

METHODS

A total of 304 newly diagnosed inpatients with coronary heart disease (CHD) were selected as the subjects in the present study. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis was performed to detect the T1128C polymorphism.

RESULTS

Of the 304 CHD patients, only one patient showed the T1128/C1128 genotype in the NPY gene, the others were all the T1128/T1128 genotype.

CONCLUSIONS

The T1128C polymorphism of the NPY gene is population specific and extremely low in a Chinese population.