Alcohol consumption alters antigen-specific Th1 responses: mechanisms of deficit and repair

A Perspective Of Intestinal Immune-Microbiome Interactions In Alcohol-Associated Liver Disease

Uncovering the intricacies of the gut microbiome and how it interacts with the host immune system has opened up pathways in the search for the treatment of disease conditions. Alcohol-associated liver disease is a major cause of death worldwide. Research has shed light on the breakdown of the protective gut barriers, translocation of gut microbes to the liver and inflammatory immune response to microbes all contributing to alcohol-associated liver disease. This knowledge has opened up avenues for alternative therapies to alleviate alcohol-associated liver disease based on the interaction of the commensal gut microbiome as a key player in the regulation of the immune response. This review describes the relevance of the intestinal immune system, the gut microbiota, and specialized and non-specialized intestinal cells in the regulation of intestinal homeostasis. It also reflects how these components are altered during alcohol-associated liver disease and discusses new approaches for potential future therapies in alcohol-associated liver disease.

Chronic Alcohol Ingestion Delays T Cell Activation and Effector Function in Sepsis

Sepsis is the leading cause of death in intensive care units in the US, and it is known that chronic alcohol use is associated with higher incidence of sepsis, longer ICU stays, and higher mortality from sepsis. Both sepsis and chronic alcohol use are associated with immune deficits such as decreased lymphocyte numbers, impaired innate immunity, delayed-type hypersensitivity reactions, and susceptibility to infections; however, understanding of specific pathways of interaction or synergy between these two states of immune dysregulation is lacking. This study therefore sought to elucidate mechanisms underlying the immune dysregulation observed during sepsis in the setting of chronic alcohol exposure. Using a murine model of chronic ethanol ingestion followed by sepsis induction via cecal ligation and puncture, we determined that while CD4+ and CD8+ T cells isolated from alcohol fed mice eventually expressed the same cellular activation markers (CD44, CD69, and CD43) and effector molecules (IFN-γ, TNF) as their water fed counterparts, there was an overall delay in the acquisition of these phenotypes. This early lag in T cell activation was associated with significantly reduced IL-2 production at a later timepoint in both the CD4+ and CD8+ T cell compartments in alcohol sepsis, as well as with a reduced accumulation of CD8dim activated effectors. Taken together, these data suggest that delayed T cell activation may result in qualitative differences in the immune response to sepsis in the setting of chronic alcohol ingestion.

Prenatal alcohol exposure and childhood atopic disease: a Mendelian randomization approach

BACKGROUND

Alcohol consumption in western pregnant women is not uncommon and could be a risk factor for childhood atopic disease. However, reported alcohol intake may be unreliable, and associations are likely to be confounded.

OBJECTIVE

We aimed to study the relation between prenatal alcohol exposure and atopic phenotypes in a large population-based birth cohort with the use of a Mendelian randomization approach to minimize bias and confounding.

METHODS

In white mothers and children in the Avon Longitudinal Study of Parents and Children (ALSPAC) we first analyzed associations between reported maternal alcohol consumption during pregnancy and atopic outcomes in the offspring measured at 7 years of age (asthma, wheezing, hay fever, eczema, atopy, and total IgE). We then analyzed the relation of maternal alcohol dehydrogenase (ADH)1B genotype (rs1229984) with these outcomes (the A allele is associated with faster metabolism and reduced alcohol consumption and, among drinkers, would be expected to reduce fetal exposure to ethanol).

RESULTS

After controlling for confounders, reported maternal drinking in late pregnancy was negatively associated with childhood asthma and hay fever (adjusted odds ratio [OR] per category increase in intake: 0.91 [95% CI, 0.82-1.01] and 0.87 [95% CI, 0.78-0.98], respectively). However, maternal ADH1B genotype was not associated with asthma comparing carriers of A allele with persons homozygous for G allele (OR, 0.98 [95% CI, 0.66-1.47]) or hay fever (OR, 1.11 [95% CI, 0.71-1.72]), nor with any other atopic outcome.

CONCLUSION

We have found no evidence to suggest that prenatal alcohol exposure increases the risk of asthma or atopy in childhood.

Alcoholism and Strongyloides stercoralis: daily ethanol ingestion has a positive correlation with the frequency of Strongyloides larvae in the stools

BACKGROUND

Significantly higher prevalence of Strongyloides stercoralis has been reported in chronic alcoholic patients. The aim of this investigation was to report the prevalence of Strongyloides larvae in stools of chronic alcoholic patients with known daily ethanol intake.

METHODS

From January 2001 through December 2003 the results of fecal examinations and the daily ethanol intake were retrieved from the records of 263 chronic alcoholic and from 590 non-alcoholic male patients that sought health care at the outpatients unit of the University Hospital C A Moraes. Alcoholic patients were separated into four groups, with 150g intervals between the groups according to the daily ethanol intake.

RESULTS

(a) The frequency of Strongyloides was significantly higher in alcoholic patients than in control group (overall prevalence in alcoholic 20.5% versus 4.4% in control group; p = 0.001). Even in the group with a daily intake of ethanol equal to or less than 150g the prevalence was higher than in control group, although non significant (9.5%, versus 4.4% in control group; p = 0,071); (b) the prevalence of Strongyloides in alcoholic patients rises with the increase of ethanol intake (Pearson's Correlation Coefficient = 0.956; p = 0.022), even in patients without liver cirrhosis (Pearson's Correlation Coefficient = 0.927; p = 0.037).

CONCLUSION

These results confirm and reinforce the hypothesis that chronic alcoholism is associated with Strongyloides infection, which is in direct relationship with the severity of alcoholism, independently of the presence of liver cirrhosis.

Changes in the immune system after moderate beer consumption

BACKGROUND/AIM

Epidemiological studies have suggested that moderate alcohol consumption is associated with lower morbidity. However, intervention studies are needed to elucidate mechanisms involved. This study was aimed to determine the effects of moderate beer consumption on the immune function of healthy adults, taking into account gender differences.

METHODS

After a 30-day alcohol abstinence period, 57 healthy volunteers consumed a moderate intake of beer (330 ml for women and 660 ml for men) for 30 days. Total leukocyte and lymphocyte counts; absolute values of T-lymphocyte CD3+, CD4+, and CD8+ subsets; delayed-hypersensitivity skin response (DHSR); absolute values of B lymphocytes (CD19+) and serum immunoglobulin concentrations (IgG, IgA, and IgM); and cytokine production (IL-2, IL-4, IL-6, IL-10, IFN-gamma, and TNF-alpha) were evaluated following the abstinence and alcohol consumption periods.

RESULTS

After moderate beer consumption CD3+ cells increased only in women (p < 0.05). IgG, IgM, and IgA concentrations, as well as IL-2, IL-4, IL-10, and IFN-gamma cytokine production increased while IFN-gamma/IL-10 ratio decreased in both men and women (p < 0.05). The rest of the immunological parameters analyzed remained unchanged.

CONCLUSION

Moderate beer consumption produced an immunomodulatory effect in a healthy adult Spanish population; this effect appears to be more relevant in women than in men.

Sexual risk behaviors and substance use among alcohol abusing HIV-positive men who have sex with men

An ethnically diverse sample (79.0% men of color) of HIV seropositive (HIV+) men who have sex with men (MSM) with alcohol use disorders from the New York City metropolitan area was recruited from a variety of settings frequented by such men. Data were collected using quantitative assessments and calendar based techniques at the baseline assessment of a longitudinal study assessing the relationship between alcohol and substance use and sexual risk behaviors as well as alcohol use and HIV disease progression. Data were selected on a sample of 253 HIV+ MSM (mean age = 38.55, SD = 6.73). Of these, the majority of participants (80.2%, n=203) reported engaging in sexual behaviors with casual partners. In terms of sexual behaviors that put partners at greatest risk for HIV transmission, unprotected anal insertive intercourse was most likely to occur with unknown status casual partners (46.8%, n=95) than with either HIV negative casual partners (19.2%, n=39) or with HIV+ casual partners (40.8%, n=83). Further, bivariate analyses indicated significant relationships between the use of several substances and sexual behaviors that put partners at greatest risk for HIV transmission, as well as a significant positive relationship between drinks per drinking day and viral load.

Microbial infections, immunomodulation, and drugs of abuse

The use of recreational drugs of abuse has generated serious health concerns. There is a long-recognized relationship between addictive drugs and increased levels of infections. Studies of the mechanisms of actions of these drugs became more urgent with the advent of AIDS and its correlation with abused substances. The nature and mechanisms of immunomodulation by marijuana, opiates, cocaine, nicotine, and alcohol are described in this review. Recent studies of the effects of opiates or marijuana on the immune system have demonstrated that they are receptor mediated, occurring both directly via specific receptors on immune cells and indirectly through similar receptors on cells of the nervous system. Findings are also discussed that demonstrate that cocaine and nicotine have similar immunomodulatory effects, which are also apparently receptor mediated. Finally, the nature and mechanisms of immunomodulation by alcohol are described. Although no specific alcohol receptors have been identified, it is widely recognized that alcohol enhances susceptibility to opportunistic microbes. The review covers recent studies of the effects of these drugs on immunity and on increased susceptibility to infectious diseases, including AIDS.

Prevalence of intestinal nematodes in alcoholic patients

We report the results of a retrospective study on the frequency of intestinal nematodes among 198 alcoholic and 440 nonalcoholic patients at the University Hospital Cassiano Antonio Moraes in Vit ria, ES, Brazil. The control sample included 194 nonalcoholic patients matched according to age, sex and neighborhood and a random sample of 296 adults admitted at the same hospital. Stool examination by sedimentation method (three samples) was performed in all patients. There was a significantly higher frequency of intestinal nematodes in alcoholics than in controls (35.3% and 19.2%, respectively), due to a higher frequency of Strongyloides stercoralis (21.7% and 4.1%, respectively). Disregarding this parasite, the frequency of the other nematodes was similar in both groups. The higher frequency of S. stercoralis infection in alcoholics could be explained by immune modulation and/or by some alteration in corticosteroid metabolism induced by chronic ethanol ingestion. Corticosteroid metabolites would mimic the worm ecdisteroids, that would in turn increase the fecundity of females in duodenum and survival of larvae. Consequently, the higher frequency of Strongyloides larvae in stool of alcoholics does not necessarily reflect an increased frequency of infection rate, but only an increased chance to present a positive stool examination using sedimentation methods.

Gut-associated lymphoid T cell suppression enhances bacterial translocation in alcohol and burn injury

The mechanism of alcohol-mediated increased infection in burn patients remains unknown. With the use of a rat model of acute alcohol and burn injury, the present study ascertained whether acute alcohol exposure before thermal injury enhances gut bacterial translocation. On day 2 postinjury, we found a severalfold increase in gut bacterial translocation in rats receiving both alcohol and burn injury compared with the animals receiving either injury alone. Whereas there were no demonstrable changes in intestinal morphology in any group of animals, a significant increase in intestinal permeability was observed in ethanol- and burn-injured rats compared with the rats receiving either injury alone. We further examined the role of intestinal immune defense by determining the gut-associated lymphoid (Peyer's patches and mesenteric lymph nodes) T cell effector responses 2 days after alcohol and burn injury. Although there was a decrease in the proliferation and interferon-gamma by gut lymphoid T cells after burn injury alone; the suppression was maximum in the group of rats receiving both alcohol and burn injuries. Furthermore, the depletion of CD3(+) cells in healthy rats resulted in bacterial accumulation in mesenteric lymph nodes; such CD3(+) cell depletion in alcohol- and burn-injured rats furthered the spread of bacteria to spleen and circulation. In conclusion, our data suggest that the increased intestinal permeability and a suppression of intestinal immune defense in rats receiving alcohol and burn injury may cause an increase in bacterial translocation and their spread to extraintestinal sites.

Intracellular mechanisms responsible for exercise-induced suppression of macrophage antigen presentation

In a previous study, we demonstrated that exhaustive exercise suppressed peritoneal macrophage antigen presentation (AP). In this study, we explored the intracellular mechanism(s) responsible for this suppression. Pathogen-free male BALB/c mice (8 +/- 2 wk) were randomly assigned to either home cage control (HCC) or exhaustive exercise stress (Exh, 18-30 m/min for 3 h/day) treatment groups. The mice underwent treatments for a period of 4 days during induced peritoneal thioglycollate inflammation. Elicited macrophages were harvested, purified, and incubated with chicken ovalbumin (C-Ova, 2. 5 and 10 mg/ml) for 18 h. After macrophages were washed, they were cocultured with C-Ova-specific T cells for 48 h at which time the supernates were harvested and analyzed via ELISA for interleukin (IL)-2 as an indication of macrophage AP. There was no significant (P > 0.05) difference in macrophage AP between cells fixed with paraformaldehyde vs. those that remained unfixed, suggesting that Exh did not affect production of soluble factors influencing macrophage AP (i.e., IL-1, IL-4, PGE(2)). The ability of macrophages to generate C-Ova immunogenic peptides was analyzed using FITC-labeled C-Ova, which shows fluorescence only when degraded intracellularly. There was a significant ( approximately 20%, P < 0. 05) suppression in fluorescence in the Exh compared with HCC, indicating a possible defect in the ability of macrophages from Exh to degrade C-Ova into immunogenic peptides. Macrophages were also incubated with C-Ova immunogenic peptide in a manner identical to that for native C-Ova. We found a similar suppression ( approximately 22-38%, P < 0.05) in macrophage AP using a C-Ova peptide when compared with native C-Ova in the Exh group, indicating reduced major histocompatibility complex (MHC) II loading and/or C-Ova-MHC II complex cell surface expression. In conclusion, these data indicate an intracellular defect in the macrophage antigen processing pathway induced by Exh.

Exercise suppresses macrophage antigen presentation

This study determined the effects of exercise on the ability of macrophages (Mphi) to present antigen to T cells. Pathogen-free male Balb/c mice (8 +/- 2 wk of age) were randomly assigned to either home cage control, moderate exercise (Mod; 18 m/min, 5% grade, 0.5 h/day), exhaustive exercise (Exh, 18-30 m/min, 3 h/day), or treadmill control groups. The mice underwent treatments for 4 days during peritoneal thioglycolate inflammation. Peritoneal Mphi were harvested, purified, and incubated with chicken ovalbumin (C-OVA; 0-10 mg/ml) for 18 h. Mphi were then cocultured with C-OVA-specific T cells for 48 h, and the supernatants were analyzed via ELISA for interleukin-2 as an indication of Mphi antigen presentation (AP). Exh exhibited suppressed ( approximately 25-34%) Mphi AP across a wide range of C-OVA doses when measured immediately, 3, and 24 h postexercise. In contrast, Mod had reduced Mphi AP only at 3 h postexercise. Mphi AP was also lower in the treadmill control (4-27%) compared with the home cage control group, but was significantly higher than Exh. The reduction in Mphi AP was not due to exercise-induced differences in Mphi number, percentage, or expression of intercellular adhesion molecule-1, B7-2, or major histocompatability complex II, molecules important in AP. In conclusion, our data lend evidence that may help explain the increased incidence of infection observed after prolonged exhaustive exercise or overtraining.