Chronic Effects Of Alcohol Research Articles

Closing the Gender Gap: The Case for Gender-Specific Alcoholism Research.

As the number of women who use alcohol increases, so does the number of women who engage in alcohol abuse and develop alcohol dependence. The recent increased focus on women and gender differences in alcoholism research has largely come about following recognition that the face of alcoholism is changing, with alcoholism rates among men remaining stable and rising among women, particularly in younger women. As such, the need to understand gender differences in both acute and long-term effects of alcohol abuse has never been more critical.Gender differences in the long-term effects of chronic alcoholism on the brain and other systems are currently under debate, often with a focus on proclaiming whether men or women suffer the most impact. However, the story appears to be more complex than that. The issue of how alcoholism interacts with gender is complicated, as gender differences in many factors including alcohol metabolism, alcoholism progression, problematic drinking patterns, neurobiology, hormones, and psychiatric comorbidities will contribute to the differences in structural and functional outcomes observed experimentally across domains of inquiry. While women are now much more commonly included in studies of alcohol’s effects on the brain, there remains a need for more explicit examinations of gender effects.

The GABAAreceptor α2 subunit gene (GABRA2) is associated with alcohol-related behavior

Background Gamma-aminobutyric acid-A (GABA-A) receptors, the major inhibitory neurotransmitter receptors in the brain are implicated in the acute and chronic effects of alcohol, including tolerance, dependence and withdrawal. Various polymorphisms in the gene encoding the GABA-A receptor alpha2 subunit (GABRA2) have been associated with alcoholism and with antisocial behavior in different populations of European ancestry. As early onset of alcoholism often reflects greater severity, including a higher risk for recurrence, comorbid antisocial personality disorder and conduct disorder, Cloninger’s classification distinguishes type II alcoholism with an early onset, elevated levels of antisocial behavior and delinquency, from the type I alcoholism with a late onset, neurotic symptoms and minimal criminality. Materials and methods Genotyping of GABRA2 polymorphisms (rs567926, rs279858 and rs9291283) was performed in samples of 355 alcoholic patients of Croatian origin (280 males and 75 females) using TaqMan Real-Time allelic discrimination technique after extraction of DNA from the whole blood. The results of allelic and haplotypic analysis were compared between alcohol-dependent subjects with a combination of early onset of alcohol abuse and presence of aggressive behavior corresponding to type II alcoholism subgroup, and individuals with the late onset of alcohol abuse and without aggression corresponding to type I alcoholism subgroup, according to Cloninger. Results Cloninger’s Type I and Type II alcohol-dependent patients did not differ significantly in the frequency of the genotypes and alleles for rs567926, rs279858 or rs9291283. However, the G-T- G haplotype was more often present in the alcohol- dependent subjects with early onset of alcohol abuse and aggressive behavior, corresponding to the Cloninger type II alcoholism subgroup (χ2 = 6.102, p = 0.013). Conclusions Our results revealed a haplotypic association between the GABRA2 gene and a more severe form of alcoholism, characterized by the early onset of alcohol abuse and presence of aggressive behavior. These findings support an important role of GABA-A receptors in the susceptibility to alcoholism and highlight them as potential targets for novel therapeutics in the treatment of alcohol dependence.

Angiotensin II Plays a Critical Role in Alcohol-Induced Cardiac Nitrative Damage, Cell Death, Remodeling, and Cardiomyopathy in a Protein Kinase C/Nicotinamide Adenine Dinucleotide Phosphate Oxidase–Dependent Manner

The purpose of this study was to examine the cellular and molecular mechanisms underlying alcoholic cardiomyopathy. The mechanism for alcoholic cardiomyopathy remains largely unknown. The chronic cardiac effects of alcohol were examined in mice feeding with alcohol or isocaloric control diet for 2 months. Signaling pathways of alcohol-induced cardiac cell death were examined in H9c2 cells. Compared with controls, hearts from alcohol-fed mice exhibited increased apoptosis, along with significant nitrative damage, demonstrated by 3-nitrotyrosine abundance. Alcohol exposure to H9c2 cells induced apoptosis, accompanied by 3-nitrotyrosine accumulation and nicotinamide adenine dinucleotide phosphate oxidase (NOX) activation. Pre-incubation of H9c2 cells with urate (peroxynitrite scavenger), N(G)-nitro-L-arginine methyl ester (a nitric oxide synthase inhibitor), manganese(III) tetrakis(1-methyl-4-pyridyl)porphyrin (a superoxide dismutase mimetic), and apocynin (NOX inhibitor) abrogated alcohol-induced apoptosis. Furthermore, alcohol exposure significantly increased the expression of angiotensin II and its type 1 receptor (AT1). A protein kinase C (PKC)-α/β1 inhibitor or PKC-β1 small interfering RNA and an AT1 blocker prevented alcohol-induced activation of NOX, and the AT1 blocker losartan significantly inhibited the expression of PKC-β1, indicating that alcohol-induced activation of NOX is mediated by PKC-β1 via AT1. To define the role of AT1-mediated PKC/NOX-derived superoxide generation in alcohol-induced cardiotoxicity, mice with knockout of the AT1 gene and wild-type mice were simultaneously treated with alcohol for 2 months. The knockout AT1 gene completely prevented cardiac nitrative damage, cell death, remodeling, and dysfunction. More importantly, pharmacological treatment of alcoholic mice with superoxide dismutase mimetic also significantly prevented cardiac nitrative damage, cell death, and remodeling. Alcohol-induced nitrative stress and apoptosis, which are mediated by angiotensin II interaction with AT1 and subsequent activation of a PKC-β1-dependent NOX pathway, are a causal factor in the development of alcoholic cardiomyopathy.

Thiamin uptake by pancreatic acinar cells: effect of chronic alcohol feeding/exposure

Thiamin is important for normal function of pancreatic acinar cells, but little is known about its mechanism of uptake and about the effect of chronic alcohol use on the process. We addressed these issues using freshly isolated rat primary and rat-derived cultured AR42J pancreatic acinar cells as models. Results showed thiamin uptake by both primary and cultured AR42J pancreatic acinar cells to be via a specific carrier-mediated mechanism and that both of the thiamin transporters 1 and 2 (THTR-1 and THTR-2) are expressed in these cells. Chronic alcohol feeding of rats was found to lead to a significant inhibition of carrier-mediated thiamin uptake by pancreatic acinar cells and was associated with a significant reduction in level of expression of THTR-1 and THTR-2 at the protein and mRNA levels. Chronic exposure (96 h) of AR42J cells to alcohol also led to a significant decreased carrier-mediated thiamin uptake, an effect that was associated with a significant decrease in the activity of the human SLC19A2 and SLC19A3 promoters expressed in these cells. We also examined the effect of chronic alcohol feeding of rats on level of expression of key thiamin metabolizing enzymes (thiamin phosphokinase and thiamin pyrophosphatase) as well as on level of expression of the mitochondrial thiamin pyrophosphate transporter of pancreatic acinar cells and observed a significant inhibition in all these parameters. These results demonstrate for the first time that thiamin uptake by pancreatic acinar cells is via a carrier-mediated process and that both the THTR-1 as well as THTR-2 are expressed in these cells. Also, chronic alcohol feeding/exposure inhibits thiamin uptake process and the inhibition is, at least in part, being exerted at the transcriptional level. Furthermore, chronic alcohol feeding also negatively impacts intracellular parameters of thiamin metabolism in pancreatic acinar cells.

Interactive Effects of Chronic Binge-Like Alcohol and Shear Stress on Pregnant Uterine Endothelial NO System and Its Associated Signaling Cascades.

Interactive Effects of Chronic Binge-Like Alcohol and Shear Stress on Pregnant Uterine Endothelial NO System and Its Associated Signaling Cascades.

Chronic alcohol effects on NF‐κB genome‐wide binding dynamics during early onset of liver regeneration

The objective of this study is to characterize effects of chronic alcohol consumption on NF‐κB mediated transcriptional regulatory network dynamics during the early phase liver regeneration after 70% partial hepatectomy (PHx) at 1 and 6h post 2/3rd PHx in the rat. Rats were fed liquid diet containing 36% of total calories derived from ethanol for 5 weeks, controls were pair‐fed isocaloric liquid diet. Genome‐wide NF‐κB binding targets were detected using Roche NimbleGen ChIP‐chip microarray platform using Chromatin Immunoprecipitated (ChIP) samples, several of which were validated by ChIP‐qPCR. Our results indicate that (1) chronic ethanol diet did not increase the genome‐wide binding activity of NF‐κB at the baseline state with ~3200 target gene promoters; (2) PHx induced significant increase in NF‐κB genome‐wide binding at 1h, more so in chronic ethanol samples (5300 genes) than in controls (4000 genes). At 6h post PHx, only the control samples showed a further increase in NF‐κB promoter binding ~5500 genes. Pathway analysis revealed that NF‐κB target genes specific to the chronic ethanol group participate in key processes such as DNA methylation, cell death, proteolysis, histone modification and regulation of cell cycle. We conclude that at least some of the chronic ethanol effects on liver regeneration are mediated by altered NF‐κB binding at specific pathway genes. Research Support: NIH AA018873, AA016919.

Alcool et épilepsie : une illustration clinique entre convulsions de sevrage et neuroborréliose

This work consists in a study of the links between alcohol, a psychoactive substance and different related epileptic manifestations in order to clarify predominant factors both on conceptual, clinical and therapeutic levels. If alcohol is a frequent risk factor for seizures, its scientific evidence is less clear and ad hoc literature is rich in controversies and not firmly supported by systematic surveys. Alcohol has variable roles in the physiopathological determinism of seizures, the nosographical status of which needs to be clarified: alcohol withdrawal seizures, alcoholic epilepsy, and sometimes symptomatic epilepsy caused by coincidental disorders. A synthesis of relevant literature describing the links between alcohol and epilepsy is illustrated by a clinical case: a patient admitted in our psychiatric ward for chronic alcoholism had had two seizures questioning their nosographical status. An infectious process with protean neurological manifestations, neuroborreliosis, was diagnosed. Three distinct clinical pictures illustrate the links between alcohol and epilepsy: the first, convulsive inebriation corresponds to a seizure during severe acute alcohol intoxication. The second deals with alcohol withdrawal seizures following a partial or complete sudden withdrawal of alcohol; these are the clinical features the most documented in the literature representing, with delirium tremens, the main complication of alcohol withdrawal. The third clinical picture, alcoholic epilepsy, is characterized by repetitive seizures in patients presenting alcohol abuse without former history of epilepsy or other potentially epileptic disorder, and without relationship to alcohol withdrawal or acute alcohol intoxication. Acute and chronic effects of alcohol on central nervous system have been depicted, while a unified classification of alcohol related seizures has been recently established by Bartolomei. This classification based on the Ballenger hypothesis of kindling (1978) could explain withdrawal and hazardous seizures as clinical expressions of the same epileptogenic process over different stages. Although theoretically criticized, such a model offers a conceptual interest while able to unify the varied understanding of convulsive crises related to alcohol, and a practical one, whilst being a basis for a therapeutic approach. Our clinical case illustrates the delay in the diagnosis established after two iterative generalized seizures, 72 hours after the beginning of a programmed weaning of a patient presenting alcohol dependency. If the withdrawal seizure hypothesis was underlined, some data led to symptomatic epilepsy. Firstly atypia, the well-supervised preventive treatment of convulsion did not avoid seizures. Secondly, the EEG showed focal anomalies strongly linked in the literature with a cerebral disorder, which was confirmed by MRI; thirdly, cognitive alterations, which are not usual in alcohol dependency, were observed clinically and confirmed by neuropsychological tests. Finally a neuroborreliosis was diagnosed, while the main neuropsychiatric complications of Lyme disease were described. In accordance with the recommendations made by some authors, it appeared legitimate to consider neuroborreliosis as a potential differential diagnosis of every atypical psychiatric disorder, the interest of such an identification laying in the existence of a specific treatment.

Liquid-Diet with Alcohol Alters Maternal, Fetal and Placental Weights and the Expression of Molecules Involved in Integrin Signaling in the Fetal Cerebral Cortex

Maternal alcohol consumption during pregnancy causes wide range of behavioral and structural deficits in children, commonly known as Fetal Alcohol Syndrome (FAS). Children with FAS may suffer behavioral deficits in the absence of obvious malformations. In rodents, the exposure to alcohol during gestation changes brain structures and weights of offspring. The mechanism of FAS is not completely understood. In the present study, an established rat (Long-Evans) model of FAS was used. The litter size and the weights of mothers, fetuses and placentas were examined on gestation days 18 or 20. On gestation day 18, the effects of chronic alcohol on the expression levels of integrin receptor subunits, phospholipase-Cγ and N-cadherin were examined in the fetal cerebral cortices. Presence of alcohol in the liquid-diet reduced the consumption and decreased weights of mothers and fetuses but increased the placental weights. Expression levels of β1 and α3 integrin subunits and phospholipase-Cγ2 were significantly altered in the fetal cerebral cortices of mothers on alcohol containing diet. Results show that alcohol consumption during pregnancy even with protein, mineral and vitamin enriched diet may affect maternal and fetal health, and alter integrin receptor signaling pathways in the fetal cerebral cortex disturbing the development of fetal brains.

A New Test to Measure Attentional Bias and Cognitive Disinhibition in Drinkers, Based on the Hayling Task

To generate and pilot unfinished sentences, based on the Hayling Task of disinhibition, which could be completed with alcohol or non-alcohol words. To determine whether drinking habits influenced responses on the new sentences, which may advance understanding of the cognitive processes underlying alcohol-related behaviours. Three phases: I-Generation of appropriate sentences (via email correspondence); II-Sentence completion to establish proportion of alcohol-related and non-alcohol-related responses; III-A Hayling-style task using the sentences (laboratory-based). During the Hayling task, sentences were completed with the first word that came to mind (initiation task), and with a word that did not make semantic sense (inhibition task). In Phase III, the alcohol use disorder identification test (AUDIT) was also completed to determine whether drinking habits were related to responses. Fifteen sentences were generated and tested. Compared with low hazardous drinkers, higher hazardous drinkers gave more alcohol-related responses; persisted in giving alcohol responses in the inhibition task; and were slower to make non-alcohol-related responses. A positive correlation was found between AUDIT score and number of alcohol-related responses. A new alcohol-related sentence-completion tool, based upon the Hayling disinhibition task, was developed and piloted. Responses on the task were associated with measures of alcohol use disorders. The task can be used in research investigating the processes underlying the acute and chronic effects of alcohol, such as attentional bias and disinhibition. In future, the task could be used in conjunction with non-alcohol-related sentence completion tasks to investigate general and alcohol-specific processes of disinhibition.

Chronic alcohol exposure induced gene expression changes in the zebrafish brain

Chronic alcohol exposure affects the central nervous system, influences behavior, and induces neuroadaptive changes in vertebrate species including our own. The molecular mechanisms responsible for chronic alcohol effects have not been fully elucidated due to the complexity of alcohol's actions. Here we use zebrafish, a novel tool in alcohol research, to reveal a large number of genes that respond to chronic alcohol treatment. We demonstrate differential gene expression in response to chronic alcohol treatment using full genome DNA microarrays and find a total of 1914 genes to show a minimum of 2-fold and significant expression level change (1127 were up- and 787 were down-regulated). Approximately two-thirds of these genes had no known previous functional annotation. The results of the microarray analyses correlated well with those obtained on a selected subset of genes analyzed by quantitative real-time RT-PCR. Analyses of the differentially expressed genes with known annotations were enriched for a variety of molecular functions. Only a fraction of these known genes has been reported in the literature to be alcohol related. We conclude that the zebrafish is an excellent tool for the analysis of genes associated with alcohol's actions in vertebrates, one which may facilitate the discovery and better understanding of the mechanisms of alcohol abuse.

Addiction-like behavior in Drosophila

Alcohol abuse is a pervasive problem known to be influenced by genetic factors, yet our understanding of the mechanisms underlying alcohol addiction is far from complete. Drosophila melanogaster has been established as a model for studying the molecular mechanisms that mediate the acute and chronic effects of alcohol. However, the Drosophila model has not yet been extended to include more complex alcohol-related behaviors such as self-administration. We recently established a paradigm to characterize ethanol consumption and preference in flies. We demonstrated that flies prefer to consume ethanol-containing food over regular food, and this preference exhibits several features of alcohol addiction: flies increase ethanol consumption over time, they consume ethanol to pharmacologically relevant concentrations, they will overcome an aversive stimulus in order to consume ethanol, and they exhibit relapse after a period of ethanol deprivation. Thus, ethanol preference in flies provides a new model for studying important aspects of addiction and their underlying mechanisms. One mutant that displayed decreased ethanol preference, krasavietz, may represent a first step toward uncovering those mechanisms.

Long-term suppression of forebrain neurogenesis and loss of neuronal progenitor cells following prolonged alcohol dependence in rats

Alcohol dependence leads to persistent neuroadaptations, potentially related to structural plasticity. Previous work has shown that hippocampal neurogenesis is modulated by alcohol, but effects of chronic alcohol on neurogenesis in the forebrain subventricular zone (SVZ) have not been reported. Effects in this region may be relevant for the impairments in olfactory discrimination present in alcoholism. Here, we examined the effects of prolonged alcohol dependence on neurogenesis. Rats were sacrificed directly after 7 wk of intermittent alcohol vapour exposure, or 3, 7 or 21 d into abstinence. Proliferation was assessed using BrdU and Ki67 immunoreactivity, newly differentiated neurons (neurogenesis) as doublecortin-immunoreactivity (DCX-IR), and neural stem cells using the SOX2 marker. In the dentate gyrus, chronic dependence resulted in a pattern similar to that previously reported for acute alcohol exposure: proliferation and neurogenesis were suppressed by the end of exposure, rebounded on day 3 of abstinence, and returned to control levels by days 7 and 21. In the SVZ, proliferation was also suppressed at the end of alcohol exposure, followed by a proliferation burst 3 d into abstinence. However, in this area, there was a trend for reduced proliferation on days 7 and 21 of abstinence, and this was accompanied by significant suppression of DCX-IR, indicating a long-term suppression of forebrain neurogenesis. Finally, a decrease in the SOX2 stem cell marker was detected at days 7 and 21, suggesting long-term reduction of the SVZ stem cell pool. While suppression of hippocampal neurogenesis by alcohol dependence is transient, the suppression in the forebrain SVZ appears long-lasting.

What can we learn from the pervasive linkage of impulsivity and addictive behavior?

Trait impulsivity is consistently linked with pathological aspects of substance use. This study extends this linkage to an undergraduate population, in which scores on the Barratt Impulsivity scale were found to predict frequent binge drinking and poly-substance use. As the authors note, the acute and chronic effects of alcohol and drugs can promote impulsive behavior by impairing cortical executive functions. In this way, a preexisting tendency to impulsive behavior when coupled with exposure to psychoactive drugs could lead to a vicious cycle of frequent heavy use and a corresponding deterioration in executive functions. The authors observe that their cross-sectional data provide a basis to test this hypothesis in a longitudinal design. The data also raise a number of additional questions. First, what do the findings suggest about the role of screening and especially targeted prevention strategies in post-secondary institutions? More generally, what can we infer from the pervasive linkage of impulsivity and addictive behavior: Could trait impulsivity represent a ‘pro-dromal’ state that mimics the deficits of non-impulsive individuals who have already transitioned to pathological levels of substance use? That is, in a functional sense, are impulsive individuals quasi-addicted from the outset?

Chronic Alcohol Consumption Blunts β-Adrenergic Responsiveness in Left Ventricular Cardiomyocytes

Alcoholic cardiomyopathy (ACM) develops from long-term, excessive consumption of alcohol. Initially, ACM is asymptomatic but continued alcohol abuse leads to reductions in cardiac contractility, the onset of arrhythmias, chamber dilation and congestive heart failure. This study was carried out to examine the effects of chronic alcohol on basal and β-adrenergic-stimulated properties of Ca2+ transients during excitation-contraction (E-C) coupling. Rats were pair-fed DeCarli and Lieber control and alcohol liquid diets for 120 days prior to isolating left ventricular myocytes. Under basal conditions, there was no change in the amplitude of electrically-triggered [Ca2+]i transients (Control, 296±21nM vs. Alcoholic, 260±18 nM) or contraction (Control, 11.9±0.6 μm, Alcoholic,12.7±1.2 μm. However, a blunted inotropic response (increase over basal: Control, 90±19% vs. Alcoholic 39±10 %) was observed in the presence of submaximal isoproterenol stimulation. In addition, maximal isoproterenol and forskolin stimulation do not improve the inotropic response of the alcoholic myocytes, suggesting a functional impairment in the initial Ca2+ release steps of E-C coupling. Consistent with the reduced [Ca2+]i transient amplitude, the Ca2+ current (ICa,L) responses to isoproterenol were also markedly reduced in cardiomyocytes from alcohol-fed animals. Surprisingly, measurement of L-type calcium channel expression by dihydropyridine (DHP) binding and real-time PCR, revealed an increased number of DHP binding sites (Control Bmax = 197 ± 60 fmol/mg vs. Alcoholic Bmax = 335 ± 45 fmol/mg, P < 0.05) and α1C subunit expression (Alcoholic 2-ΔΔCt1.69 ± 0.03, Control 2-ΔΔCt0.96 ± 0.02, P< 0.0005), respectively. This loss of L-type calcium channel activity, accompanied by an increased channel expression with chronic alcohol consumption may be a precipitating factor in alcoholic heart disease, leading to the onset of other adaptive mechanisms and, eventually, the clinical syndrome of heart failure.

Impairment of Peripheral Nerve Healing After Nerve Repair in Rats Chronically Exposed To Alcohol

The aim of this study was to determine the effect of chronic alcoholism on the healing of repaired peripheral nerve and muscle. Group 1 rats (n = 9) were fed with an alcohol-free modified liquid diet (MLD) throughout the experiment and received no nerve transection or repair. Group 2 rats (n = 9) were fed the same isocaloric MLD and underwent nerve transection and repair. Group 3 (n = 7) consisted of alcoholic rats without nerve transection and repair and Group 4 (n = 8) consisted of alcoholic rats with nerve transection and repair. To assess the effects of chronic alcoholism on nerve healing, surgical procedures were applied to rats in Groups 2 and 4. After 2 months, posterior tibial nerve and gastrocnemius muscle samples were taken for histological analysis. Group 2 rats displayed a group of atrophic fibers, whereas Group 3 rats showed myophagocytosis and endomysial mononuclear infiltration and type 2 fiber atrophy. Group 4 rats displayed a large section of atrophic fibres. Axonal loss, prominent regenerative clusters and endoneural fibrosis occurred in Group 2 rats. Axonal and myelin degeneration, myelin remnants and thinly myelinated axons were exhibited in Group 3 rats, whereas severe axonal loss, myelin degeneration, regenerative clusters and endoneural fibrosis were discovered in Group 4. There was a significant difference in the number of myelinated axons among the various groups of rats. Our findings show that chronic alcoholism has a negative influence on peripheral nerve regeneration associated with a significant decrease in axon number and increased axonal degeneration.

The opposite effects of acute and chronic alcohol on lipopolysaccharide-induced inflammation are linked to IRAK-M in human monocytes.

Impaired host defense after alcohol use is linked to altered cytokine production, however, acute and chronic alcohol differently modulate monocyte/macrophage activation. We hypothesized that in human monocytes, acute alcohol induces hyporesponsiveness to LPS, resulting in decreased TNF-alpha, whereas chronic alcohol increases TNF-alpha by sensitization to LPS. We found that acute alcohol increased IL-1R-associated kinase-monocyte (IRAK-M), a negative regulator of IRAK-1, in human monocytes. This was associated with decreased IkappaB alpha kinase activity, NFkappaB DNA binding, and NFkappaB-driven reporter activity after LPS stimulation. In contrast, chronic alcohol decreased IRAK-M expression but increased IRAK-1 and IKK kinase activities, NFkappaB DNA binding, and NFkappaB-reporter activity. Inhibition of IRAK-M in acute alcohol-exposed monocytes using small interfering RNA restored the LPS-induced TNF-alpha production whereas over-expression of IRAK-M in chronic alcohol macrophages prevented the increase in TNF-alpha production. Addition of inhibitors of alcohol metabolism did not alter LPS signaling and TNF-alpha production during chronic alcohol exposure. IRAK-1 activation induces MAPKs that play an important role in TNF-alpha induction. We determined that acute alcohol decreased but chronic alcohol increased activation of ERK in monocytes and ERK inhibitor, PD98059, prevented the chronic alcohol-induced increase in TNF-alpha. In summary, inhibition of LPS-induced NFkappaB and ERK activation by acute alcohol leads to hyporesponsiveness of monocytes to LPS due to increased IRAK-M. In contrast, chronic alcohol sensitizes monocytes to LPS through decreased IRAK-M expression and activation of NFkappaB and ERK kinases. Our data indicate that IRAK-M is a central player in the opposite regulation of LPS signaling by different lengths of alcohol exposure in monocytes.

Nitric Oxide‐Mediated Intestinal Injury Is Required for Alcohol‐Induced Gut Leakiness and Liver Damage

Alcoholic liver disease (ALD) requires endotoxemia and is commonly associated with intestinal barrier leakiness. Using monolayers of intestinal epithelial cells as an in vitro barrier model, we showed that ethanol-induced intestinal barrier disruption is mediated by inducible nitric oxide synthase (iNOS) upregulation, nitric oxide (NO) overproduction, and oxidation/nitration of cytoskeletal proteins. We hypothesized that iNOS inhibitors [NG-nitro-l-arginine methyl ester (l-NAME), l-N(6)-(1-iminoethyl)-lysine (l-NIL)] in vivo will inhibit the above cascade and liver injury in an animal model of alcoholic steatohepatitis (ASH). Male Sprague-Dawley rats were gavaged daily with alcohol (6 g/kg/d) or dextrose for 10 weeks +/- l-NAME, l-NIL, or vehicle. Systemic and intestinal NO levels were measured by nitrites and nitrates in urine and tissue samples, oxidative damage to the intestinal mucosa by protein carbonyl and nitrotyrosine, intestinal permeability by urinary sugar tests, and liver injury by histological inflammation scores, liver fat, and myeloperoxidase activity. Alcohol caused tissue oxidation, gut leakiness, endotoxemia, and ASH. l-NIL and l-NAME, but not the d-enantiomers, attenuated all steps in the alcohol-induced cascade including NO overproduction, oxidative tissue damage, gut leakiness, endotoxemia, hepatic inflammation, and liver injury. The mechanism we reported for alcohol-induced intestinal barrier disruption in vitro - NO overproduction, oxidative tissue damage, leaky gut, endotoxemia, and liver injury - appears to be relevant in vivo in an animal model of alcohol-induced liver injury. That iNOS inhibitors attenuated all steps of this cascade suggests that prevention of this cascade in alcoholics will protect the liver against the injurious effects of chronic alcohol and that iNOS may be a useful target for prevention of ALD.

Relative and Combined Effects of Chronic Alcohol Consumption and HCV Infection on Serum Zinc, Copper, and Selenium

In alcoholic hepatitis, Kupffer cells are activated by intestinal gram-bacteria, leading to cytokine production and free radicals release, which, enhancing cytokine secretion, create a positive feedback loop which contributes to liver inflammation. Free radicals also damage the liver in chronic hepatitis C virus (HCV) infection, a condition frequently associated to alcohol consumption. In both situations, activity of antioxidant enzymes and of its cofactors zinc (Zn), selenium (Se), and copper (Cu) is important. This study was performed to assess the relative and combined effects of chronic alcoholism and HCV infection on serum Se, Zn, and Cu, and its relation with serum malondialdehyde (MDA) and tumor necrosis factor-α, interferon-γ, and interleukins (IL) 4, 6, and 8, in 19 HCV- alcoholic patients, 12 HCV+ alcoholic patients, nine HCV+ non-alcoholic patients, and 20 controls. Serum Zn and Se were lower in both HCV+ and HCV- alcoholic patients, whereas serum Cu was lower in HCV+ individuals. Serum Zn and Se were related to liver function derangement. MDA levels were higher in alcoholics, but no relation was observed between trace elements and MDA or cytokines, so that our results do not support a relevant role of the analyzed trace elements in the pathogenesis of chronic liver disease.

Lipid levels in sperm, eggs, and during fertilization in Xenopus laevis

Critical developmental periods, such as fertilization, involve metabolic activation, membrane fusion events such as sperm-egg or plasma membrane-cortical granule merger, and production and hydrolysis of phospholipids. However, there has been no large-scale quantification of phospholipid changes during fertilization. Using an enzymatic assay, traditional FA analysis by TLC and gas chromatography, along with a new method of phospholipid measurement involving HPLC separation and evaporative light-scattering detection, we report lipid levels in eggs, sperm, and during fertilization in Xenopus laevis. Sperm were found to contain different amounts of phospholipids as compared with eggs. During fertilization, total phosphatidylinositol, lysophosphatidylcholine, sphingomyelin, and phosphatidylserine decreased, and ceramide increased, whereas there was no change in phosphatidylcholine, cardiolipin, or phosphatidylethanolamine. FA analysis of phospholipids found numerous changes during fertilization. Because there is an increase in sn-1,2-diacylglycerol at fertilization, the FAs associated with this increase and the source of the increase in this neutral lipid were examined. Finally, activation of phospholipase C, phospholipase D, phospholipase A2, autotoxin, and sphingomyelinase at fertilization is discussed.

Chronic alcohol treatment in rats alters sleep by fragmenting periods of vigilance cycling in the light period with extended wakenings

Studies have shown that disturbed sleep produced by chronic alcohol abuse in humans can predict relapse drinking after periods of abstinence. How alcohol produces disturbed sleep remains unknown. In this study we used a novel analysis of sleep to examine the effects of alcohol on sleep patterns in rats. This analysis separates waking into multiple components and defines a period labeled vigilance cycling (VC) in which the rat rapidly cycles through various vigilance states. These VC episodes are separated by long duration wake (LDW) periods. We find that 6 weeks of alcohol (6% in a liquid diet) caused fragmentation of extended VC episodes that normally occur in the light period. However, total daily amounts of slow-wave sleep (SWS) and rapid-eye movement sleep (REMS) remained constant. The daily amount of wake, SWS, and REMS remained constant because the alcohol treated rats increased the amount of VC in the dark period, and the sleep nature of VC in the dark period became more intense. In addition, we observed more wake and less REMS early in the light period in alcohol treated rats. All effects completely reversed by day 16 of alcohol withdrawal. Comparison of the effects of chronic alcohol to acute alcohol exposure demonstrated the effects of chronic alcohol are due to adaptation and not the acute presence of alcohol. The effects of chronic alcohol treatment in rats mimic the effects reported in humans (REMS suppression, difficulty falling asleep, and difficulty remaining asleep).