Maternal Alcohol Use During Pregnancy Causes Systemic Oxidation of the Glutathione Redox System

Background: Increased systemic oxidant stress contributes to a variety of maternal complications of pregnancy. Although the antioxidant glutathione (GSH) and its oxidized component glutathione disulfide (GSSG) have been demonstrated to be significantly altered in the adult alcoholic, the effects of maternal alcohol use during pregnancy on oxidant stress in the postpartum female remain under investigation. We hypothesized that maternal alcohol use would increase systemic oxidant stress in the pregnant female, evidenced by an oxidized systemic GSH redox potential. Methods: As a subset analysis of a larger maternal language study, we evaluated the effects of alcohol consumption during pregnancy on the systemic GSH redox status of the postpartum female. Using an extensive maternal questionnaire, postpartum women where queried regarding their alcohol consumption during pregnancy. Any drinking, the occurrence of drinking >3 drinks/occasion, and heavy drinking of >5 drinks/occasion during pregnancy were noted. Using HPLC, maternal plasma samples were analyzed for GSH, oxidized GSSG and the redox potential of the GSH/GSSG antioxidant pair calculated. Results: Maternal alcohol use occurred in 25% (83/321) of our study sample. Two in ten women reported consuming >3 drinks/occasion during pregnancy, while 1 in 10 women reported consuming alcohol at >5 drinks/occasion. Any alcohol use during pregnancy significantly decreased plasma GSH (p < 0.05), while alcohol at >3 drinks/occasion or >5 drinks/occasion significantly decreased plasma GSH concentration (p < 0.05), increased the percent of oxidized GSSG (p < 0.05), and substantially oxidized the plasma GSH redox potential (p < 0.05). Conclusions: Alcohol use during pregnancy, particularly at levels >3 drinks/occasion, caused significant oxidation of the systemic GSH system in the postpartum women. The clinical ramifications of the observed alcohol‐induced oxidation of the GSH redox system on high risk pregnancies or on the exposed offspring require more accurate identification and further investigation.     

Linkage Analysis of Alcohol Dependence Symptoms in the Community

Background:  We have previously identified suggestive linkage for alcohol consumption in a community-based sample of Australian adults. In this companion paper, we explore the strength of genetic linkage signals for alcohol dependence symptoms.
Methods:  An alcohol dependence symptom score, based on DSM-IIIR and DSM-IV criteria, was examined. Twins and their nontwin siblings (1,654 males, 2,518 females), aged 21 to 81 years, were interviewed, with 803 individuals interviewed on 2 occasions, approximately 10 years apart. Linkage analyses were conducted on datasets compiled to maximize data collected at either the younger or the older age. In addition, linkage was compared between full samples and truncated samples that excluded the lightest drinkers (approximately 10% of the sample).
Results:  Suggestive peaks on chromosome 5p (LODs >2.2) were found in a region previously identified in alcohol linkage studies using clinical populations. Linkage signal strength was found to vary between full and truncated samples and when samples differed only on the collection age for a sample subset.
Conclusions:  The results support the finding that large community samples can be informative in the study of alcohol-related traits .     

Heavy Episodic Drinking and Alcohol Consumption in French Colleges: The Role of Perceived Social Norms

Background:  The effect of normative perceptions (social norms) on heavy episodic drinking (HED) behavior is well known in the U.S. college setting, but little work is available in other cultural contexts. The objective of this study is therefore to assess whether social norms of alcohol use are related to HED in France, taking account of other influential predictors.
Methods:  A cross-sectional survey was carried out among 731 second-year university students in the Paris region to explore the role of 29 potential alcohol use risk factors. The probability of heavy episodic drinking and the frequency of HED among heavy episodic drinkers were modeled independently. Monthly alcohol consumption was also assessed.
Results:  Of the students, 56% overestimate peer student prevalence of HED (37% for alcohol drinking prevalence). HED frequency rises with perceived peer student prevalence of HED. Other social norms associated with HED are perceived friends' approval of HED (increasing both HED probability and HED frequency) and perceived friend prevalence of alcohol drinking (increasing HED probability only). Cannabis and tobacco use, academic discipline, gender, and the number of friends are also identified as being associated with HED.
Conclusions:  Overestimation of peer student prevalence is not uncommon among French university students. Furthermore, perceived peer student prevalence of HED is linked to HED frequency, even after adjusting for other correlates. Interventions correcting misperceived prevalences of HED among peer students have therefore the potential to reduce the frequency of HED in this population.     

Influences of gender and age on relationships between alcohol drinking and atherosclerotic risk factors

Background: Alcohol drinking affects atherosclerotic progression mainly through blood pressure and lipid metabolism. The purpose of the present study was to clarify whether effects of alcohol drinking on atherosclerotic risk factors differ by gender and age. Methods: The database of periodic health check-ups for local district workers was used. The subjects were divided into 3 groups according to mean ethanol consumption per day (nondrinkers; light drinkers, less than 30 g per day; moderate-to-heavy drinkers, 30 g or more per day). The mean levels of each atherosclerosis-related variable in the 3 groups were compared. Results: The mean level of body mass index (BMI) was slightly but significantly lower in drinkers than in nondrinkers in the thirties, forties, and fifties age groups in men and in the twenties, thirties, forties, and fifties age groups in women, while this tendency was not found in the sixties age groups of men and women. In men, mean blood pressure was higher in moderate-to-heavy drinkers than in nondrinkers in all age groups and was higher in light drinkers than in nondrinkers only in the age groups after 40 years. Mean blood pressure of women was higher in the moderate-to-heavy drinker group than in the nondrinker group and this difference became higher with advance of age. In women, mean blood pressure was not affected by light drinking in any of the age groups except for the fifties age group. In men, serum total cholesterol was higher in drinkers than in nondrinkers in the twenties age group but was lower in drinkers than in nondrinkers at thirties or older. Serum total cholesterol in women was lower in drinkers than in nondrinkers in the age groups from twenties to forties but tended to be higher in drinkers than in nondrinkers in the sixties age group. Serum HDL cholesterol increased with advance of age from thirties to sixties in men, while it decreased with advance of age from twenties to sixties in women. Serum HDL cholesterol was higher in drinkers than in nondrinkers in all age groups of men and women, and atherogenic index, calculated by using serum total cholesterol and HDL cholesterol concentrations, was lower in drinkers than in nondrinkers in all age groups of men and women. Conclusion: Both in men and women, blood pressure and HDL cholesterol were strongly affected by alcohol drinking: the elevating effect of alcohol drinking on blood pressure was more prominent in the elderly than in the young, while the elevating effect of alcohol drinking on serum HDL cholesterol was not influenced by age. Relationships of drinking with total cholesterol and BMI vary by age and gender.     

Neuropeptide Y Signaling in the Central Nucleus of Amygdala Regulates Alcohol‐Drinking and Anxiety‐Like Behaviors of Alcohol‐Preferring Rats

Background: The neuropeptide Y (NPY) system of the central nucleus of amygdala (CeA) has been shown to be involved in anxiety and alcoholism. In this study, we investigated the molecular mechanisms by which NPY in the CeA regulates anxiety and alcohol drinking behaviors using alcohol‐preferring (P) rats as an animal model. Methods: Alcohol‐preferring rats were bilaterally cannulated targeting the CeA and infused with artificial cerebrospinal fluid (aCSF) or NPY. Alcohol drinking and anxiety‐like behaviors were assessed by the 2‐bottle free‐choice paradigm and light/dark box (LDB) exploration test, respectively. The levels of NPY and related signaling proteins were determined by the gold immunolabeling procedure. The mRNA levels of NPY were measured by in situ RT‐PCR. Double‐immunofluorescence labeling was performed to observe the colocalization of NPY and Ca²⁺/calmodulin‐dependent protein kinase IV (CaMK IV). Results: We found that NPY infusion into the CeA produced anxiolytic effects, as measured by the LDB exploration test, and also decreased alcohol intake in P rats. NPY infusion into the CeA significantly increased levels of CaMK IV and phosphorylated cAMP responsive element‐binding (pCREB) protein and increased mRNA and protein levels of NPY, but produced no changes in protein levels of CREB or the catalytic α‐subunit of protein kinase A (PKA‐Cα) in the CeA. We also observed that alcohol intake produced anxiolytic effects in P rats in the LDB test and also increased NPY expression and protein levels of pCREB and PKA‐Cα without modulating protein levels of CREB or CaMK IV, in both the CeA and medial nucleus of amygdala. In addition, we found that CaMK IV‐positive cells were co‐localized with NPY in amygdaloid structures of P rats. Conclusions: These results suggest that NPY infusion may increase the expression of endogenous NPY in the CeA, which is most likely attributable to an increase in CaMK IV‐dependent CREB phosphorylation and this molecular mechanism may be involved in regulating anxiety and alcohol drinking behaviors of P rats.     

Autoimmune Hepatitis Induced by Syngeneic Liver Cytosolic Proteins Biotransformed by Alcohol Metabolites

Background and aims: Aldehydes that are produced following the breakdown of ethanol (acetaldehyde) and lipid peroxidation of membranes (malondialdehyde) have been shown to bind (adduct) proteins. Additionally, these two aldehydes can combine (MAA) on nonsyngeneic and syngeneic proteins to initiate numerous immune responses to the unmodified part of the protein in the absence of an adjuvant. Therefore, these studies provide a potential mechanism for the development of antigen‐specific immune responses resulting in liver damage should syngeneic liver proteins be adducted with MAA. Methods: This study sought to test whether MAA‐modified syngeneic liver cytosolic proteins administered daily in the absence of adjuvant into C57BL/6 mice abrogates tolerance to initiate a MAA‐induced autoimmune‐like hepatitis. Results: In mice immunized with MAA‐modified cytosols, there was an increase in liver damage as assessed by aspartate aminotransferase/alanine aminotransferase levels that correlated with liver pathology scores and the presence of the pro‐fibrotic factors, smooth muscle actin, TGF‐β, and collagen. IgG antibodies and T‐cell proliferative responses specific for cytosolic proteins were also detected. Pro‐inflammatory cytokines were produced in the livers of animals exposed to MAA‐modified cytosols. Finally, transfer of immunized T cells to naïve animals caused biochemical and histological evidence of liver damage. Conclusions: These data demonstrate that a disease with an autoimmune‐like pathophysiology can be generated in this animal model using soluble MAA‐modified syngeneic liver cytosols as the immunogen. These studies provide insight into potential mechanism(s) that the metabolites of alcohol may play in contributing to the onset of an autoimmune‐like disease in patients with alcoholic liver disease.     

Alcohol Expectancies and Drinking Refusal Self‐Efficacy Mediate the Association of Impulsivity With Alcohol Misuse

Background: Recent work suggests that 2 biologically based traits convey risk for alcohol misuse: reward sensitivity/drive and (rash) impulsiveness. However, the cognitive mechanisms through which these traits convey risk are unclear. This study tested a model predicting that the risk conveyed by reward sensitivity is mediated by a learning bias for the reinforcing outcomes of alcohol consumption (i.e., positive alcohol expectancy). The model also proposed that the risk conveyed by rash impulsiveness (RI) is mediated by drinkers’ perceived ability to resist alcohol (i.e., drinking refusal self‐efficacy). Methods: Study 1 tested the model in a sample of young adults (n = 342). Study 2 tested the model in a sample of treatment‐seeking substance abusers (n = 121). All participants completed a battery of personality, cognitive, and alcohol use questionnaires and models were tested using structural equation modeling. Results: In both studies, the hypothesized model was found to provide a good fit to the data, and a better fit than alternative models. In both young adults and treatment‐seeking individuals, positive alcohol expectancy fully mediated the association between reward sensitivity and hazardous alcohol use. For treatment seekers, drinking refusal self‐efficacy fully mediated the association between RI and hazardous drinking. However, there was partial mediation in the young adult sample. Furthermore, neither trait was directly associated with the other cognitive mediator. Conclusions: The hypothesized model was confirmed on a large sample of young adults and replicated on a sample of treatment‐seeking substance abusers. Taken together, these findings shed further light on the mechanisms through which an impulsive temperament may convey risk for alcohol misuse.     

Laboratory Models Available to Study Alcohol‐Induced Organ Damage and Immune Variations: Choosing the Appropriate Model

The morbidity and mortality resulting from alcohol‐related diseases globally impose a substantive cost to society. To minimize the financial burden on society and improve the quality of life for individuals suffering from the ill effects of alcohol abuse, substantial research in the alcohol field is focused on understanding the mechanisms by which alcohol‐related diseases develop and progress. Since ethical concerns and inherent difficulties limit the amount of alcohol abuse research that can be performed in humans, most studies are performed in laboratory animals. This article summarizes the various laboratory models of alcohol abuse that are currently available and are used to study the mechanisms by which alcohol abuse induces organ damage and immune defects. The strengths and weaknesses of each of the models are discussed. Integrated into the review are the presentations that were made in the symposium “Methods of Ethanol Application in Alcohol Model—How Long is Long Enough” at the joint 2008 Research Society on Alcoholism (RSA) and International Society for Biomedical Research on Alcoholism (ISBRA) meeting, Washington, DC, emphasizing the importance not only of selecting the most appropriate laboratory alcohol model to address the specific goals of a project but also of ensuring that the findings can be extrapolated to alcohol‐induced diseases in humans.     

Cholinergic Mediation of Alcohol‐Induced Experimental Pancreatitis

Objectives: The mechanisms initiating pancreatitis in patients with chronic alcohol abuse are poorly understood. Although alcohol feeding has been previously suggested to alter cholinergic pathways, the effects of these cholinergic alterations in promoting pancreatitis have not been characterized. For this study, we determined the role of the cholinergic system in ethanol‐induced sensitizing effects on cerulein pancreatitis. Methods: Rats were pair‐fed control and ethanol‐containing Lieber‐DeCarli diets for 6 weeks followed by parenteral administration of 4 hourly intraperitoneal injections of the cholecystokinin analog, cerulein at 0.5 μg/kg. This dose of cerulein was selected because it caused pancreatic injury in ethanol‐fed but not in control‐fed rats. Pancreatitis was preceded by treatment with the muscarinic receptor antagonist atropine or by bilateral subdiaphragmatic vagotomy. Measurement of pancreatic pathology included serum lipase activity, pancreatic trypsin, and caspase‐3 activities, and markers of pancreatic necrosis, apoptosis, and autophagy. In addition, we measured the effects of ethanol feeding on pancreatic acetylcholinesterase activity and pancreatic levels of the muscarinic acetylcholine receptors m1 and m3. Finally, we examined the synergistic effects of ethanol and carbachol on inducing acinar cell damage. Results: We found that atropine blocked almost completely pancreatic pathology caused by cerulein administration in ethanol‐fed rats, while vagotomy was less effective. Ethanol feeding did not alter expression levels of cholinergic muscarinic receptors in the pancreas but significantly decreased pancreatic acetylcholinesterase activity, suggesting that acetylcholine levels and cholinergic input within the pancreas can be higher in ethanol‐fed rats. We further found that ethanol treatment of pancreatic acinar cells augmented pancreatic injury responses caused by the cholinergic agonist, carbachol. Conclusion: These results demonstrate key roles for the cholinergic system in the mechanisms of alcoholic pancreatitis.