Oxidative stress and an altered methionine metabolism in alcoholism

Association of Oxidative Stress with Neurological Disorders

BACKGORUND

Oxidative stress is one of the main contributing factors involved in cerebral biochemical impairment. The higher susceptibility of the central nervous system to reactive oxygen species mediated damage could be attributed to several factors. For example, neurons use a greater quantity of oxygen, many parts of the brain have higher concentraton of iron, and neuronal mitochondria produce huge content of hydrogen peroxide. In addition, neuronal membranes have polyunsaturated fatty acids, which are predominantly vulnerable to oxidative stress (OS). OS is the imbalance between reactive oxygen species generation and cellular antioxidant potential. This may lead to various pathological conditions and diseases, especially neurodegenerative diseases such as, Parkinson's, Alzheimer's, and Huntington's diseases.

OBJECTIVES

In this study, we explored the involvement of OS in neurodegenerative diseases.

METHODS

We used different search terms like "oxidative stress and neurological disorders" "free radicals and neurodegenerative disorders" "oxidative stress, free radicals, and neurological disorders" and "association of oxidative stress with the name of disorders taken from the list of neurological disorders. We tried to summarize the source, biological effects, and physiologic functions of ROS.

RESULTS

Finally, it was noted that more than 190 neurological disorders are associated with oxidative stress.

CONCLUSION

More elaborated studies in the future will certainly help in understanding the exact mechanism involved in neurological diseases and provide insight into revelation of therapeutic targets.

The Role of Amino Acids in Neurotransmission and Fluorescent Tools for Their Detection

Neurotransmission between neurons, which can occur over the span of a few milliseconds, relies on the controlled release of small molecule neurotransmitters, many of which are amino acids. Fluorescence imaging provides the necessary speed to follow these events and has emerged as a powerful technique for investigating neurotransmission. In this review, we highlight some of the roles of the 20 canonical amino acids, GABA and β-alanine in neurotransmission. We also discuss available fluorescence-based probes for amino acids that have been shown to be compatible for live cell imaging, namely those based on synthetic dyes, nanostructures (quantum dots and nanotubes), and genetically encoded components. We aim to provide tool developers with information that may guide future engineering efforts and tool users with information regarding existing indicators to facilitate studies of amino acid dynamics.

Enhanced erythrocyte antioxidant status following an 8-week aerobic exercise training program in heavy drinkers

Alcohol-induced oxidative stress is involved in the development and progression of various pathological conditions and diseases. On the other hand, exercise training has been shown to improve redox status, thus attenuating oxidative stress-associated disease processes. The purpose of the present study was to evaluate the effect of an exercise training program that has been previously reported to decrease alcohol consumption on blood redox status in heavy drinkers. In a non-randomized within-subject design, 11 sedentary, heavily drinking men (age: 30.3 ± 3.5 years; BMI: 28.4 ± 0.86 kg/m²) participated first in a control condition for 4 weeks, and then in an intervention where they completed an 8-week supervised aerobic training program of moderate intensity (50-60% of the heart rate reserve). Blood samples were collected in the control condition (pre-, post-control) as well as before, during (week 4 of the training program), and after intervention (week 8 of the training program). Samples were analyzed for total antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS), protein carbonyls (PC), uric acid (UA), bilirubin, reduced glutathione (GSH), and catalase activity. No significant change in indices of redox status in the pre- and post-control was observed. Catalase activity increased (p < 0.05) after 8 weeks of intervention compared to week 4. GSH increased (p < 0.05) after 8 weeks of intervention compared to the control condition and to week 4 of intervention. TAC, UA, bilirubin, TBARS, and PC did not significantly change at any time point. Moreover, concentrations of GSH, TBARS, and catalase activity negatively correlated with alcohol consumption. In conclusion, an 8-week aerobic training program enhanced erythrocyte antioxidant status in heavy drinkers, indicating that aerobic training may attenuate pathological processes caused by alcohol-induced oxidative stress.

Redox theory of aging: implications for health and disease

Genetics ultimately defines an individual, yet the phenotype of an adult is extensively determined by the sequence of lifelong exposures, termed the exposome. The redox theory of aging recognizes that animals evolved within an oxygen-rich environment, which created a critical redox interface between an organism and its environment. Advances in redox biology show that redox elements are present throughout metabolic and structural systems and operate as functional networks to support the genome in adaptation to environmental resources and challenges during lifespan. These principles emphasize that physical and functional phenotypes of an adult are determined by gene-environment interactions from early life onward. The principles highlight the critical nature of cumulative exposure memories in defining changes in resilience progressively during life. Both plasma glutathione and cysteine systems become oxidized with aging, and the recent finding that cystine to glutathione ratio in human plasma predicts death in coronary artery disease (CAD) patients suggests this could provide a way to measure resilience of redox networks in aging and disease. The emerging concepts of cumulative gene-environment interactions warrant focused efforts to elucidate central mechanisms by which exposure memory governs health and etiology, onset and progression of disease.

Oxidoreductive homeostasis in alcohol-dependent male patients and the risk of alcohol drinking relapse in a 6-month follow-up

Disturbances in the central signaling of reactive oxygen species (ROS) in response to energy intake are recognized as taking part in appetitive and consummative phases of eating disorders. This study aimed to verify the hypothesis that blood oxidoreductive balance can also affect demand for energy substances, such as alcoholic beverages in alcohol-dependent individuals, as well as the severity of their alcohol dependence and risk of drinking relapse. The following values were determined in the blood of 54 alcohol-dependent male patients after alcohol withdrawal, again after 4 weeks and after 6 months: the aldehyde products of lipid peroxidation (malonyl dialdehyde [MDA] and 4-hydroxynonenal [4-HNE]), nitric oxide (NO) metabolites, total antioxidant status (TAS), the blood activities of glutathione peroxidase (GSHpx), superoxide dismutase (SOD), glutathione reductase (GSHred), blood glucose, and lipids. Alcoholics who relapsed during 6 months of observation (n = 31, 57%) compared with patients who maintained alcohol abstinence for 6 months (n = 23, 43%) differed only in relation to initial and final NO metabolite serum concentrations. The risk of alcohol drinking relapse was lower in patients with an above-median initial blood concentration of NO metabolites and TAS. The oxidative stress parameters correlated with alcohol-dependence severity markers. No significant correlations between the studied antioxidant balance parameters and markers of nutritional status, including blood glucose and lipids, were found. Although the results of our study have some limitations and require further investigation, they suggest the role of oxidoreductive balance in the pathomechanisms of alcohol dependence and drinking relapse. In addition, due to a lack of association found between blood oxidative stress parameters and BMI, blood glucose, and lipid concentrations, they show the presence of disturbances in systemic ROS signaling in response to energy availability in alcoholics after alcohol withdrawal.

S-Glutathionylation and Redox Protein Signaling in Drug Addiction

Drug addiction is a chronic relapsing disorder that comes at a high cost to individuals and society. Therefore understanding the mechanisms by which drugs exert their effects is of prime importance. Drugs of abuse increase the production of reactive oxygen and nitrogen species resulting in oxidative stress. This change in redox homeostasis increases the conjugation of glutathione to protein cysteine residues; a process called S-glutathionylation. Although traditionally regarded as a protective mechanism against irreversible protein oxidation, accumulated evidence suggests a more nuanced role for S-glutathionylation, namely as a mediator in redox-sensitive protein signaling. The reversible modification of protein thiols leading to alteration in function under different physiologic/pathologic conditions provides a mechanism whereby change in redox status can be translated into a functional response. As such, S-glutathionylation represents an understudied means of post-translational protein modification that may be important in the mechanisms underlying drug addiction. This review will discuss the evidence for S-glutathionylation as a redox-sensing mechanism and how this may be involved in the response to drug-induced oxidative stress. The function of S-glutathionylated proteins involved in neurotransmission, dendritic spine structure, and drug-induced behavioral outputs will be reviewed with specific reference to alcohol, cocaine, and heroin.

Oxidative stress during alcohol withdrawal and its relationship with withdrawal severity

BACKGROUND

Oxidative parameters are altered during alcohol withdrawal and are said to contribute towards withdrawal symptoms in alcoholic patients.

AIMS

To study levels of five selected oxidative parameters during alcohol withdrawal state and after treatment of the withdrawal state and to assess the association of the oxidative parameters with the severity of alcohol withdrawal.

MATERIALS AND METHODS

This was a case-control study done in a De-addiction clinic of a tertiary teaching centre, Southern India. 50 persons having alcohol withdrawal symptoms were included. The oxidative stress parameters malondialdehyde, protein carbonyl, glutathione peroxidase, superoxide dismutase and catalase were assessed in during the withdrawal phase and again after the withdrawal had subsided. The same oxidative stress parameters were measured in the control group.

STATISTICAL ANALYSIS

Statistical analysis was done using SPSS version 17.0. One way ANOVA and Pearson correlation test were used for finding the association between the oxidative stress parameters levels and the severity of alcohol withdrawal. Multiple linear regression analysis done to predict variables associated with level of oxidative parameters.

RESULTS

During alcohol withdrawal the pro-oxidant malondialdehyde was elevated compared to that in the control group. Among the antioxidant enzymes the superoxide dismutase was higher and catalase was lower than the control group levels. After remission of the alcohol withdrawal both malondialdehyde remained higher and superoxide dismutase lower than in the control group. The levels of oxidative stress parameters not correlated with the severity of alcohol withdrawal.

CONCLUSIONS

oxidative stress parameters show changes during alcohol withdrawal and during the remission of withdrawal. However, levels of oxidative stress parameters not correlated with the severity of withdrawal.

Epigenetic alteration of the dopamine transporter gene in alcohol-dependent patients is associated with age

Chronic alcohol abuse and dependence are associated with dysfunctional dopaminergic neurotransmission in mesocorticolimbic circuits. Genetic and environmental factors have been shown to modulate susceptibility to alcohol dependence, and both may act through epigenetic mechanisms that can modulate gene expression, e.g. DNA methylation at CpG sites. Recent studies have suggested that DNA methylation patterns may change over time. However, few data are available concerning the rate of these changes in specific genes. A recent study found that hypermethylation of the promoter of the dopamine transporter (DAT) gene was positively correlated with alcohol dependence and negatively correlated with alcohol craving. The aim of the present study was to replicate these findings in a larger sample of alcohol-dependent patients and population-based controls matched for age and sex. No difference in methylation level was observed between patients and controls, and no difference in methylation level was observed before and after alcohol withdrawal in patients. However, patients with more severe craving showed a trend towards lower DAT methylation levels (P = 0.07), which is consistent with previous findings. Furthermore, in our overall sample, DAT methylation levels increased with age. Interestingly, a separate analysis of patients suggested that this finding was mainly driven by the patient group. Although the present data do not clarify whether chronic alcohol abuse is responsible for this phenomenon or merely enhances an ageing-specific process, our findings suggest that hypermethylation in alcohol-dependent patients is a consequence, rather than a cause, of the disorder.

Anthocyanins protect against ethanol-induced neuronal apoptosis via GABAB1 receptors intracellular signaling in prenatal rat hippocampal neurons

Here, we investigated the possible involvement of gamma-aminobutyric acid B1 receptor (GABAB1R) in mediating the protective effects of black soybean anthocyanins against ethanol-induced apoptosis in prenatal hippocampal neurons because GABARs are known to play an important role in the development of central nervous system. Treatments were performed on primary cultures of prenatal rat hippocampal neurons transfected with or without GABAB1R small interfering RNA (siRNA). The results showed that, when ethanol treatment was followed by anthocyanins treatment, cellular levels of proapoptotic proteins such as Bax, activated caspase-3, and cleaved poly (ADP-ribose) polymerase 1 (PARP-1) were decreased, and the cellular level of the antiapoptotic protein Bcl-2 was increased compared to treatment with ethanol alone. Furthermore, the effects of ethanol on cellular levels of GABAB1R and its downstream signaling molecules such as protein kinase A, calcium/calmodulin-dependent protein kinase II (CaMKII), and phosphorylated cAMP response element binding protein were diminished or reversed by anthocyanins treatment. The ability of anthocyanins to reverse the effects of ethanol on cellular levels of Bax, Bcl-2, active caspase-3, cleaved PARP-1, GABAB1R, and CaMKII were abrogated in cells transfected with GABAB1R siRNA. In a GABAB1R-dependent manner, anthocyanins also inhibited the ability of ethanol to elevate intracellular free Ca(2+) level and increase the proportion of cells with low mitochondrial membrane potential in the population. Cell apoptosis assay and morphological studies also confirmed the neuroprotective effect of anthocyanins against ethanol via GABAB1R. Our data suggest that GABAB1R plays an important role in the neuroprotective effects of anthocyanins against ethanol.

Alcohol withdrawal and brain injuries: beyond classical mechanisms

Unmanaged sudden withdrawal from the excessive consumption of alcohol (ethanol) adversely alters neuronal integrity in vulnerable brain regions such as the cerebellum, hippocampus, or cortex. In addition to well known hyperexcitatory neurotransmissions, ethanol withdrawal (EW) provokes the intense generation of reactive oxygen species (ROS) and the activation of stress-responding protein kinases, which are the focus of this review article. EW also inflicts mitochondrial membranes/membrane potential, perturbs redox balance, and suppresses mitochondrial enzymes, all of which impair a fundamental function of mitochondria. Moreover, EW acts as an age-provoking stressor. The vulnerable age to EW stress is not necessarily the oldest age and varies depending upon the target molecule of EW. A major female sex steroid, 17β-estradiol (E2), interferes with the EW-induced alteration of oxidative signaling pathways and thereby protects neurons, mitochondria, and behaviors. The current review attempts to provide integrated information at the levels of oxidative signaling mechanisms by which EW provokes brain injuries and E2 protects against it.

Anthocyanins: are they beneficial in treating ethanol neurotoxicity?

Heavy alcohol exposure produces profound damage to the developing central nervous system (CNS) as well as the adult brain. Children with fetal alcohol spectrum disorders (FASD) have a variety of cognitive, behavioral, and neurological impairments. FASD currently represents the leading cause of mental retardation. Excessive alcohol consumption is associated with Wernicke-Korsakoff syndrome (WKS) and neurodegeneration in the adult brain. Although the cellular/molecular mechanism underlying ethanol's neurotoxicity has not been fully understood, it is generally believed that oxidative stress plays an important role. Identification of neuroprotective agents that can ameliorate ethanol neurotoxicity is an important step for developing preventive/therapeutic strategies. Targeting ethanol-induced oxidative stress using natural antioxidants is an attractive approach. Anthocyanins, a large subgroup of flavonoids present in many vegetables and fruits, are safe and potent antioxidants. They exhibit diverse potential health benefits including cardioprotection, anti-atherosclerotic activity, anti-cancer, anti-diabetic, and anti-inflammation properties. Anthocyanins can cross the blood-brain barrier and distribute in the CNS. Recent studies indicate that anthocyanins represent novel neuroprotective agents and may be beneficial in ameliorating ethanol neurotoxicity. In this review, we discuss the evidence and potential of anthocyanins in alleviating ethanol-induced damage to the CNS. Furthermore, we discuss possible underlying mechanisms as well as future research approaches necessary to establish the therapeutic role of anthocyanins.

Alterations in oxidative stress status during early alcohol withdrawal in alcoholic patients

BACKGROUND/PURPOSE

Alcohol-induced oxidative stress is the result of the combined production of reactive oxygen species [ROS; e.g. malondialdehyde (MDA), an index of lipid peroxidation] and impairment of antioxidant defenses [e.g. superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), which are involved in the elimination of ROS]. Little is known about the oxidative stress markers among patients with alcohol dependence in Taiwan. This study aimed to investigate serial alterations of various oxidative stress markers during early detoxification in alcoholic patients.

METHODS

We enrolled 121 inpatients who fulfilled the DSM-IV-TR criteria for alcohol dependence, and 19 healthy controls. Fasting serum MDA level and antioxidant activity, including SOD, CAT and GPX, were measured at baseline in both groups, and after 1 and 2 weeks of detoxification in alcoholic patients.

RESULTS

MDA level in alcoholics was higher at baseline than in healthy controls. It decreased after 1 week of detoxification, and normalized at week 2. SOD and GPX activities remained significantly lower throughout the 2-week period. CAT activity in alcoholics was comparable to that in the controls at baseline, but decreased at week 1 of detoxification, and was significantly lower than that in the controls after 2 weeks. Moreover, baseline MDA level was correlated with baseline CAT activity in alcoholics; the magnitude of the decrease in MDA level was correlated with the decrease in CAT activity following the 1-week detoxification.

CONCLUSION

The findings suggest severe oxidative stress and weakened antioxidant activity in alcoholic patients, and limited changes in oxidative stress in the early stages of alcohol withdrawal.

The correlation between early alcohol withdrawal severity and oxidative stress in patients with alcohol dependence

Oxidative stress is enhanced in alcoholic patients. This clinical study aimed to explore the correlation between alcohol withdrawal severity and two oxidative stress markers, malondialdehyde (MDA) and superoxide dismutase (SOD). Seventy-six inpatients fulfilled the DSM-IV-TR criteria for alcohol dependence and 19 healthy controls were enrolled. Serum MDA level and SOD activity were measured within 24 h of alcohol detoxification. The severity of alcohol withdrawal was evaluated by the Chinese version of the revised Clinical Institute Withdrawal Assessment for Alcohol Scale (CIWA-Ar-C) every 8 h. Average and highest scores of the CIWA-Ar-C at the first day were recorded as the baseline withdrawal severity. We compared the differences of MDA and SOD between groups, and examined the correlation between baseline withdrawal severity and oxidative stress markers. Compared to controls, serum MDA levels were significantly elevated and SOD activity was significantly lowered in alcoholic patients. In stepwise multiple regression analysis, MDA was the only variable significantly correlated with the average (beta=0.48, p<0.0001) and highest (beta=0.47, p<0.0001) CIWA-Ar-C scores at the first day of detoxification. In agreement with previous studies, alcoholic patients encountered high oxidative stress. Although there was a correlation between early withdrawal severity and MDA levels, the meanings of the correlation are worth further studies in the future.

Alcohol related changes in regulation of NMDA receptor functions

Long-term alcohol exposure may lead to development of alcohol dependence in consequence of altered neurotransmitter functions. Accumulating evidence suggests that the N-methyl-D-aspartate (NMDA) type of glutamate receptors is a particularly important site of ethanol's action. Several studies showed that ethanol potently inhibits NMDA receptors (NMDARs) and prolonged ethanol exposition leads to a compensatory "up-regulation" of NMDAR mediated functions. Therefore, alterations in NMDAR function are supposed to contribute to the development of ethanol tolerance, dependence as well as to the acute and late signs of ethanol withdrawal.A number of publications report alterations in the expression and phosphorylation states of NMDAR subunits, in their interaction with scaffolding proteins or other receptors in consequence of chronic ethanol treatment. Our knowledge on the regulatory processes, which modulate NMDAR functions including factors altering transcription, protein expression and post-translational modifications of NMDAR subunits, as well as those influencing their interactions with different regulatory proteins or other downstream signaling elements are incessantly increasing. The aim of this review is to summarize the complex chain of events supposedly playing a role in the up-regulation of NMDAR functions in consequence of chronic ethanol exposure.

Significant impact of MTHFR C677T polymorphism on plasma homovanillic acid (HVA) levels among alcohol-dependent patients

The enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR) synthesizes 5-methyltetrahydrofolate. It plays a critical role in homocysteine metabolism. A high impact of MTHFR C677T polymorphism on plasma homocysteine levels has been observed among alcoholics. Recent studies indicate that homocysteine has toxic effects on dopaminergic neurons. Thus it lowers levels of homovanillic acid (HVA) in the striatal region in rats. Alcoholics had significantly lower plasma HVA concentrations compared with healthy controls. Aim of this study is to elucidate whether HVA plasma levels in alcoholics are influenced by MTHFR C677T polymorphism. A total of 142 alcohol-dependent patients and 101 healthy controls were examined regarding plasma HVA concentration and MTHFR C677T genotype. Blood samples of alcoholics were obtained after a minimum of 22 days of abstinence. Among alcohol-dependent patients MTHFR C677T polymorphism was significantly associated with plasma HVA levels: carriers of MTHFR C677T T-allele had significantly lower HVA plasma levels compared with homozygote carriers of C-allele: 11.9 ng/ml versus 14.4 ng/ml (chi2: 5.39; P = 0.02). In healthy control subjects plasma HVA levels did not differ significantly between MTHFR C677T T-allele carriers and homozygote carriers of C-allele: 15.1 ng/ml versus 15.3 ng/ml (chi2: 0.04; P = 0.82). The data suggest an influence of MTHFR C677T polymorphism on plasma HVA among alcohol-dependent patients. This might be due to neurotoxic effects of homocysteine on the dopaminergic system or direct impairment of monoamine metabolism. Future studies should try to elucidate whether this effect is reversible during alcohol abstinence.

Methylenetetrahydrofolate reductase C677T-polymorphism and its association with alcohol withdrawal seizure

BACKGROUND

Elevated homocysteine plasma levels are considered as a risk factor for the occurrence of seizures during alcohol withdrawal. Homocysteine plasma concentrations seem to be influenced by the methylenetetrahydrofolate reductase (MTHFR) C677T-polymorphism. It was investigated whether the T-allele of the MTHFR C677T-polymorphism is associated with alcohol dependence, alcohol withdrawal seizure (WS), or the daily amount of alcohol consumption.

METHODS

A group of 102 healthy controls and 221 alcoholic patients, including 97 patients with a history of mild withdrawal symptoms (MWS) and 70 patients with a history of alcohol WS, were genotyped, and personal data were collected for statistical evaluation in a case-control design.

RESULTS

The T-allele is significantly associated with WS by comparing alcoholic patients with a history of WS (T-allele frequency: 0.39) and healthy controls (T-allele frequency: 0.28) (p=0.03). Although there was no significant difference between alcoholic patients with only MWS and alcoholic patients with a history of WS, a trend for the T-allele frequency among the analyzed subgroups was noticed: T-allele frequency increased from f(T)=0.28 in healthy controls to f(T)=0.33 in alcoholic patients with MWS up to f(T)=0.40 in alcohol-dependent men having a WS. Differences between healthy male controls and male alcoholic patients concerning the T-allele frequency also turned out to be significant [f(T)=0.27 vs f(T)=0.37; p=0.03]. Daily alcohol intake was independent of T-allele carrier status in alcohol-dependent patients.

CONCLUSION

The present study suggests an influence of the MTHFR C677T-polymorphism on the etiology of alcohol WS and alcohol dependence in men in a western European population. An influence of MTHFR C677T on the daily amount of alcohol intake before admission among alcohol-dependent patients could not be shown.

Lowered DNA methyltransferase (DNMT-3b) mRNA expression is associated with genomic DNA hypermethylation in patients with chronic alcoholism

DNA methyltransferases (DNMTs) are involved within the epigenetic control of DNA methylation processes. Recently, it has been shown that the genomic DNA methylation in patients with alcoholism is increased. In the present controlled study we observed a significant decrease of mRNA expression of DNMT-3a and DNMT-3b when comparing alcoholic patients (n = 59) with healthy controls (n = 66): DNMT-3a (t = -2.38, p = 0.019), DNMT-3b (t = -2.65, p = 0.008). No significant differences were seen for DNMT-1 and Mbd-2 (Methyl-CpG-Binding-Domain protein 2) expression. Additionally, we observed a significant negative correlation between DNMT-3b expression and the blood alcohol concentration (r = -0.45, p = 0.003) which might explain the decrease of DNMT-3b mRNA expression in alcoholic patients. Using a multivariate model we observed that the increase (10%) of genomic DNA methylation in patients with alcoholism was significantly associated with their lowered DNMT-3b mRNA expression (multiple linear regression, p = 0.014). Since methylation of DNA is an important epigenetic factor in regulation of gene expression these findings may have important implications for a possible subsequent derangement of epigenetic control in these patients.

Does ascorbate/L-Cys/L-Met mixture protect different parts of the rat brain against chronic alcohol toxicity?

Chronic ingestion of high levels of alcohol may cause oxidative stress that results in the formation, through alcohol metabolism, of excess free radicals, acetaldehyde, lipid and protein oxidation, and their reactivity products. These harmful molecules may trigger oxidative damage to neurons and can cause cell death. It is hypothesized that cysteine-methionine and vitamin C may neutralize these harmful compounds while potentiating the antioxidant capacity of the cell or tissue. In the present study, rats were fed regular diets and were maintained for 90 days in (1) the control group, (2) the alcoholic group, which was given 2.5 g of 50% ethanol/kg body weight administered intragastrically every other day, or (3) the alcoholic with antioxidant supplement group, to whom 2.5 g of 50% ethanol/kg body weight + a solution that contained 200 mg vitamin C, 100 mg cysteine, and 100 mg methionine was administered intragastrically every other day. The mean blood alcohol level was raised by 40% in the alcoholic group compared with the control group, but, compared with the alcoholic group, the alcohol level was decreased by 30% in the antioxidant-supplemented group. In keeping with blood alcohol levels, oxidized protein and lipid content in the cerebrum, brain stem, and cerebellum were low in the control group, higher in the antioxidant-supplemented group, and highest in the alcoholic group. The mean total thiol level was higher in the antioxidant-supplemented group than in the alcoholic and control groups. It is interesting to note that the level of total glutathione in the cerebrum and cerebellum in the alcoholic group was lower than in the control and antioxidant-supplemented groups. In conclusion, long-term alcohol administration led to increased levels of oxidized protein and lipids in the cerebrum, brain stem, and cerebellum of rats. Simultaneous intake of ascorbate/l-cys/l-met and ethanol attenuated the amount of oxidation that occurred, which suggested that cysteine, methionine, and vitamin C may play a protective role in the central nervous system against oxidative damage caused by alcohol consumption. In addition, the mean alcohol level was increased in the alcoholic group compared with the control group. The level of total glutathione was significantly decreased in the cerebellum of the alcoholic group, and oxidative damage was noted in various parts of the brain in this group. These findings suggest that oxidative stress plays a pathogenetic role in brain damage related to chronic alcoholism.

Biological markers to predict previous alcohol withdrawal seizures: a risk assessment

Recent studies have shown that both, elevated homocysteine and prolactin plasma levels are associated with a higher risk of alcohol withdrawal seizures. The aim of this study was to evaluate the predictive qualities of a combined assessment of homocysteine and prolactin for previous alcohol withdrawal seizures. Therefore, 117 male patients suffering from alcohol dependency were included into the study. Homocysteine was measured directly at admission, prolactin the morning following admission for detoxification treatment. Pearson's chi(2)-test showed significant results for the combined assessment of both parameters (chi(2) = 14.71, p = 0.001). Multivariate logistic regression also revealed significant predictive qualities (p = 0.001, OR = 9.23, 95%CI = 2.36-36.05). A combination of both, homocysteine and prolactin, may help to assess the individual risk of alcohol withdrawal seizures in clinical practice.

Short-term cognition deficits during early alcohol withdrawal are associated with elevated plasma homocysteine levels in patients with alcoholism

Higher plasma homocysteine levels have been found in actively drinking alcoholics as well as in early abstinent patients. Furthermore, elevated homocysteine levels are associated with cognitive decline in dementia and in healthy elderly people. The aim of this prospective study was to investigate a possible association between homocysteine serum levels and clinically well known cognitive deficits during alcohol withdrawal. We examined 89 patients (67 men, 22 women) during early withdrawal treatment. Cognitive function was assessed using the c.I.-Test. Patients with cognitive deficits showed significantly higher homocysteine serum levels (Mann-Whitney-U, p=0.004) than patients without cognitive deficits, while the difference in blood alcohol concentration was not significant. Using logistic regression analysis, cognitive deficits were best predicted by high homocysteine serum levels (Wald chi2=4.071, OR=1.043, 95% CI 1.001-1.086, p<0.05), which was confirmed by Receiver Operating Curves (AUC=0.68, 95% CI=0.57-0.79, p=0.004). The present results show first evidence of an association between elevated plasma homocysteine levels in alcoholics and cognition deficits in patients undergoing alcohol withdrawal.

Alcoholism-associated hyperhomocysteinemia and previous withdrawal seizures

BACKGROUND

Higher homocysteine levels were found in actively drinking alcoholics as well as in early abstinent patients. Furthermore, it has been shown that high homocysteine levels predicted first-onset alcohol withdrawal seizures. The aim of the present study was to determine plasma homocysteine levels in actively drinking alcoholics and patients with early abstinence in order to evaluate whether there is an additional association between elevated plasma homocysteine levels and a history of alcohol withdrawal seizures.

METHODS

Two groups of patients with an established diagnosis of alcohol dependence were studied. Group A comprised 56 consecutively admitted alcoholics who had been abstinent from alcohol between 24 to 72 hours before hospitalization. Group B consisted of 144 consecutively recruited alcoholics who were admitted - acutely intoxicated - for withdrawal treatment. Furthermore, groups were divided into two subgroups: patients with and without a history of alcohol withdrawal seizures.

RESULTS

Alcoholics of GROUP B with a history of withdrawal seizures had significantly (p<.0001) higher homocysteine levels than actively drinking patients without seizures in their history: 42.0 micromol/l (SD 26.4) versus 22.5 micromol/l (SD 11.4). Using a logistic regression analysis, history withdrawal seizures in Group B but not in Group A patients were best predicted by a high homocysteine level at admission (Wald chi2=15.5, p<.0001; odds ratio 1.11, 95% CI 1.05-1.20).

CONCLUSIONS

Homocysteine levels on admission may be a useful screening method to identify actively drinking patients with a higher risk of alcohol withdrawal seizures.

Evaluation of oxidative stress measurements in obstructive sleep apnea syndrome

Assessment of reactive oxygen species (ROS) is highly important in neurodegenerative disorders and neuroleptic treatment. However, conflicting results have been reported, which may arise from methodological difficulties. Obstructive sleep apnea (OSA) syndrome with episodic hypoxia-reoxygenation is proposed as a human model for the investigation of ROS measurements. Despite a broad analytical approach comprising lipid peroxidation and amino acid oxidation products, oxidative DNA damage, and activity of the antioxidant defense, only plasma malondialdehyde (MDA) and urinary o,o'-dityrosine seemed to be appropriate, robust biomarkers of oxidative stress, which are also simple enough for routine clinical use. MDA concentrations correlated with a duration of nocturnal desaturation below 85% (r = 0.77, p<0.0005), and o,o'-dityrosine levels decreased after therapy (p<0.05) as a function of baseline concentrations (r = -0.61, p<0.05). Gender effects in ROS generation also have to be considered. At present, we recommend the application of several oxidative stress measurements at different time points, preferably involving plasma MDA and urinary o,o'-dityrosine.

DNA hypermethylation of the alpha synuclein promoter in patients with alcoholism

The aim of this study was to investigate whether the DNA methylation pattern within the alpha synuclein promoter region is altered in intoxicated and early abstinence patients with alcoholism undergoing alcohol withdrawal. We observed a significant increase of the alpha synuclein promoter DNA methylation in patients with alcoholism which was significantly associated with their elevated homocysteine levels. No significant differences of the promoter DNA methylation within a control gene (presenilin-1) in alcoholics and controls were found. The present results hint to a gene specific DNA promoter hypermethylation within the alpha synuclein gene. Since hypermethylation of DNA is an important epigenetic factor in the down regulation of gene expression and since alpha synuclein has been linked to craving these findings may explain the reduced value of craving under alcohol drinking conditions.

The High Atherosclerotic Risk Among Epileptics: the Atheroprotective Role of Multivitamins

Neurologists have little concern about the high atherosclerotic risk among epileptics. Recent evidences mount that chronic epilepsy and prolonged use of antiepileptic drugs (AEDs) are associated with multiple risk factors that are critically implicated in pathobiology and dysfunction of the vessel wall through complex molecular mechanisms that promote atherogenesis. This review is concerned with three metabolic alterations, which are attributed as major risk factors for atherosclerosis among epileptics: altered metabolism of a) homocysteine (Hcy), b) lipids and lipoproteins, and c) uric acid. Most conventional AEDs reduce folic acid levels, thereby raising Hcy levels. Hyperhomosysteinemia is recently believed to induce endothelial dysfunction and promote atherosclerosis through complex oxidative and excitatory neurotoxic molecular mechanisms. However, Hcy itself is a convulsing substance with increased seizure recurrence and intractability to antiepileptic medications. AEDs can disturb lipid metabolism with resultant hypercholestrolemia and dyslipidemia, common recognized risks for atherosclerosis. Altered uric acid metabolism is common among epileptics. Uric acid has been implicated in endothelial cell damage and decreased endothelial nitric oxide bioavailability. In the presence of atherosclerotic milieu, uric acid interacts with other substrate toxicities and increased reactive oxygen species, accelerating atherosclerosis. The above information forms the rationale for future routine screening and correction of such metabolic alterations in epileptics. A convincing argument now develops that routine polyvitamin supplementation (folic acid, vitamin B12, vitamin B6, vitamin C, vitamin E, and beta-carotene) becomes increasingly important for women and men receiving AEDs at all ages. The atheroprotective effect of multivitamins is through their antioxidant and anti-inflammatory effects together with their lipid and Hcy lowering effects.

Role of TNF-alpha in ethanol-induced hyperhomocysteinemia and murine alcoholic liver injury

We previously reported a link between ethanol-induced elevation of homocysteine, endoplasmic reticulum (ER) stress, and alcoholic liver injury in the murine model of intragastric ethanol feeding. We studied the role of TNFalpha in this setting by using TNFR1 knockout mice (C57 BL/6). There was a 7.4-fold increase of homocysteine in wild-type and a 6-fold increase in TNFR1 knockout mice with intragastric alcohol exposure for 4 weeks. Plasma TNFalpha increased in the wild-type (18.4 +/- 3.3 pg/mL vs. 8.4 +/- 1.3 pg/mL (control)) and in the knockouts (12.9 +/- 1.4 pg/mL vs. 7.2 +/- 1.6 pg/mL (control)). Similar extent of fatty liver was observed in both types. Increased ALT was observed in both groups. Necroinflammatory foci were increased significantly in ethanol-fed knockouts but not to the same extent as in the ethanol-fed wild type. Increase of hepatic apoptosis and reduction of S-adenosyl-L-methionine was detected in both types of animals fed ethanol. ER stress demonstrated by RT-PCR of mRNA of selective ER stress markers GRP78, CHOP, and SREBP1 was increased equivalently in both types of mice. Betaine administration decreased ER stress in conjunction with attenuation of the elevated plasma homocysteine in both types of animals. Betaine increased hepatic S-adenosyl-L-methionine by 28 fold in the knockouts and by 24-fold in wild type. In conclusion, TNFalpha makes a moderate contribution to the ALT elevation, necroinflammation, apoptosis, a small contribution to the fatty liver and no contribution to hyperhomocysteinemia and ER stress in intragastric alcohol fed mice.

Analysis of hippocampal atrophy in alcoholic patients by a Kohonen feature map

We investigated the correlation of hippocampal volume with homocysteine, folate, vitamin B12 and B6 in alcoholic patients and healthy controls applying a Kohonen feature map (KFM) and conventional statistics. Representation of subjects on the KFM suggested an inverse correlation of hippocampal volume with blood levels of homocysteine and correlation with folate and vitamin B6. In conventional statistical analyses (t-test) reduced folate and increased homocysteine was found in alcoholics compared to healthy controls (p < 0.01). In female alcoholics vitamin B6 was reduced significantly (p = 0.03). Multiple linear regression analyses showed a significant correlation between average hippocampal volume and homocysteine (p < 0.001). KFM proved to be a sensitive tool for visualisation of statistical correlations in data sets even if no further statistical information is available.

Voxel-based morphometry of human brain with age and cerebrovascular risk factors

The objectives of this study were to evaluate the correlations of the volumes of the gray matter and white matter with age, and the correlations of the tissue probabilities of the gray matter and white matter with age and several cerebrovascular risk factors. We obtained magnetic resonance (MR) images of the brain and clinical information from 769 normal Japanese subjects. We processed the MR images automatically by correcting for inter-individual differences in brain size and shape, and by segmenting the MR images into the gray matter and white matter. Volumetry of the brain revealed a significant negative correlation between the gray matter volume and age, which was not observed between white matter volume and age. Voxel-based morphometry showed that age, systolic blood pressure, and alcohol drinking correlated with the regional tissue probabilities of the gray matter and white matter.

Homocysteine as a neurotoxin in chronic alcoholism

There is evidence from in vitro and in vivo studies that homocysteine induces neuronal damage and cell loss by both excitotoxicity and different apoptotic processes. Clinical evidence suggest a strong relationship between higher plasma homocysteine levels and brain atrophy in healthy elderly subjects as well as in elderly at risk of and with Alzheimer's disease. Chronic alcoholism leads to elevated plasma homocysteine levels, as shown by clinical investigations and animal experiments. In addition, an association between brain atrophy and increased levels of homocysteine in chronic alcoholism was shown. This may have important implications for the pathogenesis of alcoholism-associated brain atrophy. Furthermore, taking into account that high plasma homocysteine levels are helpful in the prediction of alcohol withdrawal seizures, early anticonvulsive therapy could prevent this severe complication. Homocysteine plays a role in a shared biochemical cascade involving overstimulation of N-methyl-D-aspartate (NMDA) receptors, oxidative stress, activation of caspases, DNA damage, endoplasmic reticulum and mitochondrial dysfunction. These mechanisms are believed to be important in the pathogenesis of both excitotoxicity and apoptotic neurotoxicity. Prospective intervention studies may show whether the incidence of complications of alcohol withdrawal or alcoholism-associated disorders can be reduced by therapeutic measures with early lowering of elevated homocysteine levels (e.g. folate administration). The most important pathophysiological and pathobiochemical features of glutamatergic neurotransmission and of ethanol-induced hyperhomocysteinaemia are reviewed in relation to their excitotoxic and apoptotic potential.

Activation of methionine synthase by insulin-like growth factor-1 and dopamine: a target for neurodevelopmental toxins and thimerosal

Methylation events play a critical role in the ability of growth factors to promote normal development. Neurodevelopmental toxins, such as ethanol and heavy metals, interrupt growth factor signaling, raising the possibility that they might exert adverse effects on methylation. We found that insulin-like growth factor-1 (IGF-1)- and dopamine-stimulated methionine synthase (MS) activity and folate-dependent methylation of phospholipids in SH-SY5Y human neuroblastoma cells, via a PI3-kinase- and MAP-kinase-dependent mechanism. The stimulation of this pathway increased DNA methylation, while its inhibition increased methylation-sensitive gene expression. Ethanol potently interfered with IGF-1 activation of MS and blocked its effect on DNA methylation, whereas it did not inhibit the effects of dopamine. Metal ions potently affected IGF-1 and dopamine-stimulated MS activity, as well as folate-dependent phospholipid methylation: Cu(2+) promoted enzyme activity and methylation, while Cu(+), Pb(2+), Hg(2+) and Al(3+) were inhibitory. The ethylmercury-containing preservative thimerosal inhibited both IGF-1- and dopamine-stimulated methylation with an IC(50) of 1 nM and eliminated MS activity. Our findings outline a novel growth factor signaling pathway that regulates MS activity and thereby modulates methylation reactions, including DNA methylation. The potent inhibition of this pathway by ethanol, lead, mercury, aluminum and thimerosal suggests that it may be an important target of neurodevelopmental toxins.

Genetic study of alcoholism and novel gene expression in the alcoholic brain

Alcohol dependence may result from neuroadaptation involving alteration of gene expression after long-term alcohol exposure. The systematic study of gene expression profiles of the human alcoholic brain was initiated using the method of polymerase chain reaction (PCR)-differential display and was followed by DNA microarray. To date, more than 100 alcohol-responsive genes have been identified from the frontal cortex, motor cortex and nucleus accumbens of the human brain. These genes have a wide range of functions in the brain and indicate diverse actions of alcohol on neuronal function. This review discusses the current information on the genetic basis of alcoholism and the induction and characterization of these alcohol-responsive genes.

Homocysteine induces cell death of rat astrocytes in vitro

From several disease states as well as from animal models homocysteine is known to be toxic to the central nervous system. Homocysteine is an excitatory amino acid which markedly enhances the vulnerability of neuronal cells to excitotoxic, apoptotic, and oxidative injury in vitro and in vivo. Both beneficent and deleterious effects of astrocytes in the pathogenesis of different neurodegenerative disorders have been described. However, data about the neurotoxic effect of homocysteine on astrocytes are lacking. The present study therefore was undertaken to investigate a possible cytotoxic effect of homocysteine on cortical astrocytes in vitro. Exposure to D,L-homocysteine resulted in a time and dose-dependent gliotoxic effect at doses of 2 mM and above (P<0.001). This is comparable to homocysteine toxicity observed in other cell culture models and implies that a participation of astrocytes in homocysteine-induced neurodegeneration may be considered. The results of the present in vitro studies may therefore have implications for understanding the pathogenesis of neurotoxicity linked to neurodegenerative disorders (e.g. Alzheimer's disease, glaucomatous optic neuropathy). This is the first study to report that homocysteine induces cell death of astrocytes. The mechanisms by which homocysteine induces cell death of astrocytes warrant further study.

Effects of prostaglandin E1, melatonin, and oxytetracycline on lipid peroxidation, antioxidant defense system, paraoxonase (PON1) activities, and homocysteine levels in an animal model of spinal cord injury

STUDY DESIGN

Investigation of the effects of prostaglandin E1, melatonin, and oxytetracycline on lipid peroxidation, antioxidant and paraoxonase activities, and homocysteine levels in an experimental model of spinal cord injury.

OBJECTIVES

To determine the antioxidant efficacy of prostaglandin E1, melatonin, and oxytetracycline and whether paraoxonase and homocysteine can be used as monitoring parameters in the acute oxidative stress of spinal cord injury.

SUMMARY OF BACKGROUND DATA

Melatonin has been found useful in spinal cord injury in previous studies. No study exists investigating the effects of melatonin, prostaglandin E1, and oxytetracycline as well as the response type of paraoxonase enzyme and homocysteine levels in the acute oxidative stress of spinal cord injury.

METHODS

Sixty-three male albino Wistar rats were anesthetized with 400 mg/kg chloral hydrate and divided into 5 groups. The G1 (n = 7) control group provided the baseline levels. G2-G5 underwent T3-T6 total laminectomies and spinal cord injuries by clip compression at the T4-T5 levels. Medications were applied to G3-G5 right after clip compression. Hence, G2 constituted laminectomy + injury, G3 laminectomy + injury + prostaglandin E1; G4 laminectomy + injury + melatonin, and G5 laminectomy + injury + oxytetracycline groups. Animals were decapitated either the first or fourth hour after injury. Spinal cord tissue and blood malonyldialdehyde and plasma homocysteine levels, plasma glutathione peroxidase, superoxide dismutase, paraoxonase activities were assayed. The SPSS 9.0 program was used for statistical analysis and graphics. Intergroup comparisons were made by Bonferroni corrected Mann Whitney U test (P < 0.025) and intragroups comparisons by Wilcoxon Rank test (P < 0.03).

RESULTS

In injury groups, plasma homocysteine levels decreased and paraoxonase activities increased as erythrocyte superoxide dismutase levels and plasma glutathione peroxidase activities decreased in parallel to increases of tissue and blood malonyldialdehyde levels. These alterations were relatively suppressed by prostaglandin E1, melatonin, and oxytetracycline administrations in varying degrees. Melatonin was the most powerful agent, particularly at the fourth hour. Oxytetracycline was also effective, both at the first and fourth hour. Prostaglandin E1 was effective in comparison to injury group, but not as much as melatonin and oxytetracycline.

CONCLUSIONS

Melatonin and oxytetracycline are effective in preventing lipid peroxidation in spinal cord injury. Paraoxonase and homocysteine can be used in monitoring the antioxidant defense system as well as superoxide dismutase and plasma glutathione peroxidase, both in injury and medicated groups.

Alcohol abuse and dependence: psychopathology, medical management and dental implications

BACKGROUND

The authors review the clinical features, epidemiology, pathophysiology, medical management, dental findings and dental treatment of patients with alcoholism.

LITERATURE REVIEWED

The authors conducted a MEDLINE search for 1995 through 2001 using the key terms of alcoholism, epidemiology, pathophysiology, treatment and dentistry. Reports selected for further review included those published in English in peer-reviewed journals. The authors gave preference to articles reporting randomized, controlled trials.

CONCLUSIONS

Alcoholism is a chronic and progressive psychiatric illness that afflicts more than 14 million Americans. It is characterized by a loss of control over the use of alcohol, resulting in impaired social functioning, and the consequent development of medical illnesses. The disease arises in genetically vulnerable people when they are overwhelmed by their cravings for the alcohol-associated euphoria that results from the actions of several neurotransmitter systems in the brain's pleasure center. New medications to counteract alcohol-induced neurotransmission imbalance may assist patients in reducing their craving.

CLINICAL IMPLICATIONS

The prevalence of dental disease usually is extensive because of a disinterest in performing appropriate oral hygiene techniques and diminished salivary flow. Concurrent abuse of tobacco products worsens dental disease and heightens the risk of developing oral cancer. Identification of the alcohol-abusing patient, a cancer-screening examination, preventive dental education, and use of saliva substitutes and anticaries agents are indicated. Special precautions must be taken when performing surgery and when prescribing or administering analgesics, antibiotics or sedative agents that are likely to have an adverse interaction with alcohol or psychiatric medications.

Hyperhomocysteinemia as a new risk factor for brain shrinkage in patients with alcoholism

Chronic alcohol consumption can induce brain atrophy, whereby the exact mechanism of brain damage in alcoholics remains unknown. There is evidence that chronic alcoholism is associated with hyperhomocysteinemia. Homocysteine is an excitatory amino acid which markedly enhances the vulnerability of neuronal cells to excitotoxic and oxidative injury in vitro and in vivo. The present volumetric magnetic resonance imaging study included 52 chronic alcoholics and 30 non-drinking healthy controls. Patients were active drinkers and had an established diagnosis of alcohol dependence. We investigated the influence of different variables on the hippocampal volume of patients suffering from chronic alcoholism. We observed that pathological raised levels of plasma homocysteine showed the most significant correlation to hippocampal volume reduction (P<0.001, multiple regression analysis). Raised plasma levels of homocysteine are associated with hippocampal (brain) atrophy in alcoholism.

Effects of in vivo treatment of rats with trimethyltin chloride on respiratory properties of rat liver mitochondria

Liver mitochondria isolated from rats treated in vivo with trimethyltin chloride show stimulation of respiration using glutamate/malate as substrate, and a transient inhibition on rates of respiration using palmitoyl-L-carnitine as substrate. This phenomenon was observed with both ADP- and FCCP-stimulated respiration. In contrast, rates of respiration by liver mitochondria isolated from rats treated in vivo with trimethyltin chloride, following prior treatment with clofibrate, were inhibited when glutamate/malate was respiratory substrates. With palmitoyl-L-carnitine no effect of trimethyltin chloride was observed. In vitro treatment of rat liver mitochondria, or of rat liver homogenates, led to the expected, powerful inhibition of respiration. The synthesis of ATP by liver mitochondria isolated from rats treated in vivo with trimethyltin chloride was not inhibited compared to mitochondria isolated from control rats. Similarly, ATP synthesis by mitochondria isolated from rats treated with clofibrate, before treatment with trimethyltin chloride, was not inhibited. We, therefore, conclude that the powerful inhibitory effects of trimethyltin found in vitro, is not expressed in vivo during the first 36 hr following administration. In vivo treatment of rats with trimethyltin chloride caused a marked increase in hepatic levels of taurine and glycine, while levels of glutathione and glutamine were diminished. This is consistent with an enhanced oxidative stress in the liver. Our findings lead to the conclusion that increased oxidative stress, rather than inhibition of the mitochondrial ATPase, is a likely major cause of the in vivo toxic effects due to trimethyltin chloride.

Risk assessment of alcohol withdrawal seizures with a Kohonen feature map

Recently, it has been suggested that alcohol-induced hyperhomocysteinaemia in patients suffering from chronic alcoholism might be a risk factor for alcohol withdrawal seizures. In the present follow-up study 12 patients with chronic alcoholism who suffered from withdrawal seizures had significantly higher levels of homocysteine (Hcy) on admission (71.43 +/- 25.84 mol/l) than patients (n = 37) who did not develop seizures (32.60 +/- 24.87 mol/l; U = 37.50, p = 0.0003). Using a logistic regression analysis, withdrawal seizures were best predicted by a high Hcy level on admission (p < 0.01; odds ratio 2.07). Based on these findings we developed an artificial neural network system (Kohonen feature map, KFM) for an improved prediction of the risk of alcohol withdrawal seizures. Forty-nine patients with chronic alcoholism (12 with alcohol withdrawal seizures and 37 without seizures) were randomized into a training set and a test set. Best results for sensitivity of the KFM was 83.3% (five of six seizure patients were predicted correctly) with a specificity of 94.4% (one false positive prediction of 19 patients). We conclude that in patients with alcohol-induced hyperhomocysteinaemia the KFM is a useful tool to predict alcohol withdrawal seizures.