GLUTAMIC ACID IN WITHDRAWAL AND WEANING IN PATIENTS CLASSIFIED ACCORDING TO CLONINGER'S AND LESCH'S TYPOLOGIES

Glutamate contributes to alcohol hepatotoxicity by enhancing oxidative stress in mitochondria

Chronic alcohol intoxication is associated with increased oxidative stress. However, the mechanisms by which ethanol triggers an increase in the production of reactive oxygen species (ROS) and the role of mitochondria in the development of oxidative stress has been insufficiently studied. The biochemical and proteomic data obtained in the present work suggest that one of the main causes of an increase in ROS generation is enhanced oxidation of glutamate in response to long-term alcohol exposure. In the course of glutamate oxidation, liver mitochondria from alcoholic rats generated more superoxide anion and H₂O₂ than in the presence of other substrates and more than control organelles. In mitochondria from alcoholic rats, rates of H₂O₂ production and NAD reduction in the presence of glutamate were almost twice higher than in the control. The proteomic study revealed a higher content of glutamate dehydrogenase in liver mitochondria of rats subjected to chronic alcohol exposure. Simultaneously, the content of mitochondrial catalase decreased compared to control. Each of these factors stimulates the production of ROS in addition to ROS generated by the respiratory chain complex I. The results are consistent with the conclusion that glutamate contributes to alcohol hepatotoxicity by enhancing oxidative stress in mitochondria.

Behavioral effects of transcranial direct current stimulation (tDCS) induced dorsolateral prefrontal cortex plasticity in alcohol dependence

Transcranial Direct Current Stimulation (tDCS) has been shown to reduce acute substance craving in drug addicts, and improve cognition in neuropsychiatric patients. Here we aimed to explore further tDCS induced behavioral and neurophysiological modulation including assessment of relapse rate over a prolonged time course in alcoholism. We examined the effects of repeated anodal tDCS (2mA, 35 cm(2), 20min) over the left dorsolateral prefrontal cortex (DLPFC) on relapse to the use of alcohol in alcoholics from outpatient services, who received additional routine clinical treatment. Furthermore, event related potentials (ERPs), cognitive and frontal executive processes, craving, depressive and anxiety symptoms were obtained before and after treatment. From thirteen alcoholic subjects, seven were randomized to sham-tDCS and six to real tDCS treatment (once a week for five consecutive weeks). Depressive symptoms and craving were reduced to a larger extent in the tDCS group compared to the sham group (p=0.005 and p=0.015, respectively). On the other hand, active tDCS was able to block the increase in neural activation triggered by alcohol related and neutral cues in prefrontal cortex (PFC) as indexed by ERP as seen in the sham-tDCS group. Finally, there was a trend for increased change in executive function in the tDCS group compared to the sham-tDCS group (p=0.082), and, similarly, a trend for more relapses in the tDCS group compared to sham tDCS (four alcoholic subjects (66.7%) vs. one (14.3%), p=0.053).These results confirm the previous findings of tDCS effects on craving in alcoholism and also extend these findings as we showed also tDCS-related mood improvement. However, potential increase in relapse is possible; thus the clinical value of an increase in craving and improvement in depression and executive function needs to be carefully assessed in further studies; including investigation of optimal parameters of stimulation.

Auditory event-related potentials (P3) and cognitive changes induced by frontal direct current stimulation in alcoholics according to Lesch alcoholism typology

Frontal lobe dysfunction is a hallmark of alcohol dependence. Recent studies have shown that a simple but powerful technique of cortical modulation--transcranial direct current stimulation (tDCS)--can induce significant cognitive changes. We therefore aimed to assess the clinical and electrophysiological (as indexed by P3) effects of tDCS of left dorsolateral prefrontal cortex (DLPFC) in different types of alcoholic patients according to Lesch's typology. We enrolled 49 alcoholic subjects, aged between 18 and 75 yr, during the subacute abstinence period to participate in this study. Subjects underwent event-related potential (ERP) registration of alcohol-related and neutral sounds before, during and after active tDCS (1 mA, 35 cm², during 10 min) or sham procedure in a counterbalanced and randomized order. Frontal assessment battery (FAB) and five items of the Obsessive Compulsive Drinking Scale were applied at the beginning and at the end of each experimental session. ERP analysis showed an increase in the mean amplitude of P3 associated with alcohol-related sounds after tDCS. This effect was not seen for neutral sounds. This change was more pronounced in Lesch IV alcoholics. Secondary exploratory analysis showed a significant improvement of FAB performance after active tDCS compared to sham tDCS in Lesch IV alcoholics only. We showed clinical and electrophysiological evidence of tDCS-induced frontal activity enhancement that was specific for Lesch IV alcoholics. Given that frontal dysfunction may contribute to the loss of control over drinking behaviour, local increase in frontal activity induced by tDCS might have a beneficial clinical impact in the future.

GABA-A receptor genes do not play a role in genetics of Lesch's typology in Caucasian subjects

INTRODUCTION

Lesch's typology differentiates alcoholics into different treatment response subgroups. The effects of ethanol are mediated, to an important extent, via the GABA-ergic system.

MATERIAL AND METHODS

We have evaluated the linkage disequilibrium patterns and haplotype frequencies of GABRG1 and GABRA2 genes in 133 alcoholics divided according to Lesch's typology and in 145 matched controls.

RESULTS

Besides several relationships at a threshold of statistical significance, we found no significant differences in the haplotype distribution of these genes between alcoholics and controls.

CONCLUSIONS

Lesch's typology may not be related with the genotype of alcoholics - at least in terms of genes with an established role in the development of dependency.

Comparison of alcohol-dependent patients at a gastroenterological and a psychiatric ward according to the Lesch alcoholism typology: implications for treatment

AIMS

To assess the clinical and biological status of alcohol-dependent patients admitted to a psychiatric or a gastroenterological ward, assessing and comparing dimensions important for prescribing treatment for withdrawal and relapse prevention.

METHODS

Eighty patients, alcohol-dependent according to international classification of diseases tenth revision and diagnostic and statistical manual, text revised, version IV, admitted to the Vienna General Hospital between January 2005 and  November 2006, were examined, of whom 44 were admitted to the psychiatric ward and 36 to the gastroenterological ward. Dimensions of alcohol dependence were assessed using a computerized structured interview, the Lesch alcoholism typology (LAT). Biological markers and the model for end-stage liver disease (MELD) score defined the severity of alcohol-related physical disturbances.

RESULTS

As might be expected, gastroenterological patients had more advanced physical diseases than psychiatric patients, and affective disorders and suicidal tendencies were significantly commoner among the psychiatric patients. Thus, LAT Type II patients were overrepresented at the gastroenterological ward and LAT Type III patients at the psychiatric ward.

CONCLUSION

The severity of somatic diseases and psychiatric disorders as well as the distribution of the four types according to Lesch differ between alcohol-dependent patients admitted to a psychiatric ward or a gastroenterological ward. Regarding the positive long-term outcome, different evidence-based medical treatment approaches for withdrawal and relapse prevention are needed for these patients.

Two types of classification in female alcoholism

Two types of alcoholism with distinct clinical features and mode of inheritance have been identified in male alcoholics. The relevant studies, however, have given consistent results in men but not in women. The current study tested the hypothesis that the type I and II classification is also valid in women. A sample of 103 hospitalised alcohol-dependent women were given face-to-face structured interviews considering four different classification criteria sets devised for differentiation of alcoholism type I and II and type A and B along with SCID I and II. The two types of classification could be replicated with three of the four criteria sets, 73 women being allocated to the larger cluster C1, and 30 women to a smaller cluster C2. Comparing the patients from both clusters with each other, eight variables were identified which excellently discriminate between the groups. The two types of classification for alcoholism could also be found in a female sample. A type II of female alcohol-dependent patient was identified, characterized by parental alcoholism and paternal and patient's tendency for violent behavior. Type I lacks these characteristics. Early identification of the type II female alcoholic may be clinically important.

Cognitive components of frontal lobe function in alcoholics classified according to Lesch's typology

AIMS

This study examined the frontal lobe cognitive function and the mental state among patients with different types of alcohol dependence according to Lesch's typology.

METHODS

The frontal assessment battery (FAB) and the mini-mental status examination (MMSE) were given to 170 patients with alcoholism from a Brazilian outpatient service classified by Lesch's typology and to 40 non-alcoholic controls matched for age, gender, socio-demographic characteristics and education.

RESULTS

Of the alcoholic sample, 21.2% were classified as Type I, 29.4% as Type II, 28.8% as Type III and 20.6% as Type IV. Alcoholics showed significantly lower overall scores on the MMSE and the FAB as compared to non-alcoholic subjects. Type IV alcoholics had lower MMSE and FAB overall scores as compared to non-alcoholic controls and also to all other types of alcoholic subjects. However, Type II and III subjects with alcoholism also had lower overall FAB scores, but not overall MMSE scores, as compared to non-alcoholic controls. The FAB subsets of motor programming, sensitivity to interference and inhibitory control were significantly reduced in Types II, III and IV alcoholics as compared to non-alcoholic subjects, but only motor programming remained impaired in Type IV alcoholics with preserved mental function.

CONCLUSIONS

Executive dysfunctions in alcohol dependence seem to vary depending upon the type of alcoholism. Therefore, the determination of clinical type of alcohol dependence by applying Lesch's typology, along with brief mental state and frontal function examinations, is of clinical relevance in the examination of alcoholics and provides significant clues for more directed forms of alcohol dependence treatment.

Herp mRNA expression in patients classified according to Lesch's typology

Chronic alcoholism is associated with hyperhomocysteinemia. Herp (homocysteine-induced endoplasmic reticulum [ER] protein) levels are elevated as a response to ER stress prior to mitochondrial dysfunction and cell death. The Lesch classification system has been applied in many studies and has been found useful. This study was undertaken to assess Herp mRNA expression in actively drinking patients with alcoholism who were classified according to Lesch's typology. Herp mRNA expression levels were measured by quantitative PCR in the blood of 76 male alcoholic patients. Patients were classified according to Lesch's typology (type I-IV). With respect to Lesch's typology, a significant difference in Herp mRNA expression regarding the four subtypes could be shown (F[3,72]=2.83, P=.044). In a logistic regression model (dependent variable Herp dichotomized by a median-split; adjusted for age and homocysteine levels) the subtype II differed statistically significant from the others (odds ratio, 5.75; 95% confidence interval, 2.07-15.98; P=.001). Type II alcoholic patients had a statistically significant higher expression of Herp mRNA due to upregulation of the expression of this neuroprotective cell non-chaperone by toxic effects of ethanol. These findings might explain why type II patients do not express severe withdrawal symptomatology (i.e., withdrawal seizures). These findings may be useful in the understanding and treatment considerations of different subtypes of alcohol dependence.

Apolipoprotein E gene polymorphism and previous alcohol withdrawal seizures

Aim of this study was to investigate the possible association of apolipoprotein E (ApoE) gene polymorphism with a history of alcohol withdrawal seizures. We included 194 patients with alcohol dependence who were divided into patients with (SZ+) and without (SZ-) previous alcohol withdrawal seizures. ApoE genotypes were determined using PCR. For statistical analysis we examined the number of ApoE alleles (ApoE2: n=36; ApoE3: n=311; ApoE4: n=41). A significant positive association with a positive history of withdrawal seizures (SZ+) was found in the ApoE3 allele group (Fisher's exact test: p=0.006) while a significant negative association was observed in the ApoE2 allele group (Fisher's exact test: p=0.029). For the ApoE4 allele group no significant differences were found regarding a history of withdrawal seizures. Our findings suggest an association between the apolipoprotein E3 gene variant and an elevated risk of alcohol withdrawal seizures. These preliminary results must be validated in further studies.

Role of Appetite-Regulating Peptides in Alcohol Craving: An Analysis in Respect to Subtypes and Different Consumption Patterns in Alcoholism

BACKGROUND

A role of appetite-regulating peptides like leptin and ghrelin in the neurobiology of alcohol craving has been proposed by several studies. Aim of this analysis was to search for differences regarding an association between these peptides and alcohol craving with respect to different subtypes and beverage consumption patterns in patients with alcohol dependence.

METHODS

We analyzed a sample of 188 patients at admission for alcohol detoxification regarding leptin and ghrelin (n=117) serum levels. Craving was measured using the Obsessive Compulsive Drinking Scale (OCDS). Patients were classified according to Lesch's typology of alcohol dependence and according to their preferred type of alcoholic beverage (beer, wine, spirits).

RESULTS

Using general linear models to analyze a possible interaction between subtypes and leptin/ghrelin levels with respect to craving, we found a significant positive association for leptin in patients of Lesch's types 1 and 2, and in patients consuming beer or wine. Ghrelin levels showed a significant trend regarding an association with craving in patients of Lesch's type 1. In the other subgroups we found no significant results.

CONCLUSIONS

Our findings show that appetite-regulating peptides may be of special importance regarding alcohol craving in subtypes of patients. This may explicate at least in part previous contradictory findings.