Mechanisms of suppression of cellular immunity induced by ethanol

Early-Stage Moderate Alcohol Feeding Dysregulates Insulin-Related Metabolic Hormone Expression in the Brain: Potential Links to Neurodegeneration Including Alzheimer's Disease

Background

Alzheimer's disease (AD), one of the most prevalent causes of dementia, is mainly sporadic in occurrence but driven by aging and other cofactors. Studies suggest that excessive alcohol consumption may increase AD risk.

Objective

Our study examined the degree to which short-term moderate ethanol exposure leads to molecular pathological changes of AD-type neurodegeneration.

Methods

Long Evans male and female rats were fed for 2 weeks with isocaloric liquid diets containing 24% or 0% caloric ethanol (n = 8/group). The frontal lobes were used to measure immunoreactivity to AD biomarkers, insulin-related endocrine metabolic molecules, and proinflammatory cytokines/chemokines by duplex or multiplex enzyme-linked immunosorbent assays (ELISAs).

Results

Ethanol significantly increased frontal lobe levels of phospho-tau, but reduced Aβ, ghrelin, glucagon, leptin, PAI, IL-2, and IFN-γ.

Conclusions

Short-term effects of chronic ethanol feeding produced neuroendocrine molecular pathologic changes reflective of metabolic dysregulation, together with abnormalities that likely contribute to impairments in neuroplasticity. The findings suggest that chronic alcohol consumption rapidly establishes a platform for impairments in energy metabolism that occur in both the early stages of AD and alcohol-related brain degeneration.

Dynamic immune and exosome transcriptomic responses in patients undergoing psychostimulant methamphetamine withdrawal

Methamphetamine (METH) addiction and withdrawal cause serious harm to both the immune system and nervous system. However, the pathogenesis remains largely unknown. Herein, we investigated the peripheral cytokines and exosomal transcriptome regulatory networks in the patients with METH use disorders (MUDs) undergoing withdrawal. Twenty-seven cytokines were simultaneously assessed in 51 subjects, including 22 at the acute withdrawal (AW) stage and 29 at the protracted withdrawal (PW) stage, and 31 age and gender-matched healthy controls (HCs). Compared to the HCs, significantly decreased levels of interleukin (IL)-1β, IL-9, IL-15, Basic FGF, and MIP1a, increased levels of IL-1rα, IL-6, Eotaxin IP-10, VEGF, and RANTES were identified in AW. These disturbances were mostly or partly restored to the baseline in PW. However, the cytokines IL-6, IL-7, and IL-12p70 were consistently increased even after one year of withdrawal. Besides, a significant decrease in CD3+T and CD4+T cell numbers was observed in AW, and the diminishment was restored to baseline in PW. Comparatively, there were no statistically significant changes in CD8+T, NK, and B cells. Furthermore, the exosomal mRNAs and long non-coding RNAs (lncRNA) were profiled, and the lncRNA-miRNA-mRNA networks were constructed and associated with METH AW and PW stages. Notably, the chemokine signaling was remarkably upregulated during AW. By contrast, the differentially expressed mRNAs/lincRNAs were significantly enriched in neurodegeneration-related diseases. Taken together, a group of METH withdrawal-related cytokines and exosomal mRNA/lncRNA regulatory networks were obtained, which provides a useful experimental and theoretical basis for further understanding of the pathogenesis of the withdrawal symptoms in MUDs.

Translational Implications of the Alcohol-Metabolizing Enzymes, Including Cytochrome P450-2E1, in Alcoholic and Nonalcoholic Liver Disease

Fat accumulation (hepatic steatosis) in alcoholic and nonalcoholic fatty liver disease is a potentially pathologic condition which can progress to steatohepatitis (inflammation), fibrosis, cirrhosis, and carcinogenesis. Many clinically used drugs or some alternative medicine compounds are also known to cause drug-induced liver injury, which can further lead to fulminant liver failure and acute deaths in extreme cases. During liver disease process, certain cytochromes P450 such as the ethanol-inducible cytochrome P450-2E1 (CYP2E1) and CYP4A isozymes can be induced and/or activated by alcohol and/or high-fat diets and pathophysiological conditions such as fasting, obesity, and diabetes. Activation of these P450 isozymes, involved in the metabolism of ethanol, fatty acids, and various drugs, can produce reactive oxygen/nitrogen species directly and/or indirectly, contributing to oxidative modifications of DNA/RNA, proteins and lipids. In addition, aldehyde dehydrogenases including the mitochondrial low Km aldehyde dehydrogenase-2 (ALDH2), responsible for the metabolism of acetaldehyde and lipid aldehydes, can be inactivated by various hepatotoxic agents. These highly reactive acetaldehyde and lipid peroxides, accumulated due to ALDH2 suppression, can interact with cellular macromolecules DNA/RNA, lipids, and proteins, leading to suppression of their normal function, contributing to DNA mutations, endoplasmic reticulum stress, mitochondrial dysfunction, steatosis, and cell death. In this chapter, we specifically review the roles of the alcohol-metabolizing enzymes including the alcohol dehydrogenase, ALDH2, CYP2E1, and other enzymes in promoting liver disease. We also discuss translational research opportunities with natural and/or synthetic antioxidants, which can prevent or delay the onset of inflammation and liver disease.

Gut microbiota in alcoholic liver disease: Pathogenetic role and therapeutic perspectives

Alcoholic liver disease (ALD) is the commonest cause of cirrhosis in many Western countries and it has a high rate of morbidity and mortality. The pathogenesis is characterized by complex interactions between metabolic intermediates of alcohol. Bacterial intestinal flora is itself responsible for production of endogenous ethanol through the fermentation of carbohydrates. The intestinal metabolism of alcohol produces a high concentration of toxic acetaldehyde that modifies gut permeability and microbiota equilibrium. Furthermore it causes direct hepatocyte damage. In patients who consume alcohol over a long period, there is a modification of gut microbiota and, in particular, an increment of Gram negative bacteria. This causes endotoxemia and hyperactivation of the immune system. Endotoxin is a constituent of Gram negative bacteria cell walls. Two types of receptors, cluster of differentiation 14 and Toll-like receptors-4, present on Kupffer cells, recognize endotoxins. Several studies have demonstrated the importance of gut-liver axis and new treatments have been studied in recent years to reduce progression of ALD modifying gut microbiota. It has focused attention on antibiotics, prebiotics, probiotics and synbiotics.

Substance use disorders: psychoneuroimmunological mechanisms and new targets for therapy

An estimated 76.4 million people worldwide meet criteria for alcohol use disorders, and 15.3 million meet criteria for drug use disorders. Given the high rates of addiction and the associated health, economic, and social costs, it is essential to develop a thorough understanding of the impact of substance abuse on mental and physical health outcomes and to identify new treatment approaches for substance use disorders (SUDs). Psychoneuroimmunology is a rapidly expanding, multidisciplinary area of research that may be of particular importance to addiction medicine, as its focus is on the dynamic and complex interactions among behavioral factors, the central nervous system, and the endocrine and immune systems (Ader, 2001). This review, therefore, focuses on: 1) the psychoneuroimmunologic effects of SUDs by substance type and use pattern, and 2) the current and future treatment strategies, including barriers that can impede successful recovery outcomes. Evidence-based psychosocial and pharmacotherapeutic treatments are reviewed. Psychological factors and central nervous system correlates that impact treatment adherence and response are discussed. Several novel therapeutic approaches that are currently under investigation are introduced; translational data from animal and human studies is presented, highlighting immunotherapy as a promising new direction for addiction medicine.

Microbial translocation in chronic liver diseases

The intestinal microflora is not only involved in the digestion of nutrients, but also in local immunity, forming a barrier against pathogenic microorganisms. The derangement of the gut microflora may lead to microbial translocation, defined as the passage of viable microorganisms or bacterial products (i.e., LPS, lipopeptides) from the intestinal lumen to the mesenteric lymph nodes and other extraintestinal sites. The most recent evidence suggests that microbial translocation (MT) may occur not only in cirrhosis, but also in the early stage of several liver diseases, including alcoholic hepatopathy and nonalcoholic fatty liver disease. Different mechanisms, such as small intestinal bacterial overgrowth, increased permeability of intestinal mucosa, and impaired immunity, may favor MT. Furthermore, MT has been implicated in the pathogenesis of the complications of cirrhosis, which are a significant cause of morbidity and mortality in cirrhotic subjects. Therapeutic strategies aiming at modulating the gut microflora and reducing MT have focused on antibiotic-based options, such as selective intestinal decontamination, and nonantibiotic-based options, such as prokinetics and probiotics. In particular, probiotics may represent an attractive strategy, even though the promising results of experimental models and limited clinical studies need to be confirmed in larger randomized trials.

Effect of alcohol drinking and cigarette smoking on neutrophil functions in adults

In recent years, the effects of smoking and excessive alcohol consumption on immune function have been studied, due to a high prevalence of infection or cancer in heavy drinkers, and the combination of smoking and drinking was considered to be a carcinogenic risk. However, the effect of smoking and drinking on systemic immune function has yet to be clearly understood. In this study, we investigated neutrophil functions (reactive oxygen species (ROS) productive activity, phagocytic ability and serum opsonic activity) and their relationship with alcohol consumption or amount of smoking. In total there were 731 male and female adult subjects who participated in the Iwaki Health Promotion Project in 2005. Multiple regression analysis showed a trend of increased ROS production in male subjects and a statistically significant decrease was observed in phagocytic activity caused by smoking in female subjects. In other words, oxidative stress caused by smoking in male subjects may be involved in ROS production from neutrophils. Decreased phagocytic activity of neutrophils caused by smoking suggests that host defense functions were impaired in female subjects. A relationship between neutrophil functions and the amount of alcohol consumption was not observed.

Gut microbiota and probiotics in chronic liver diseases

There is a strong relationship between liver and gut: the portal system receives blood from the gut, and intestinal blood content activates liver functions. The liver, in turn, affects intestinal functions through bile secretion into the intestinal lumen. Alterations of intestinal microbiota seem to play an important role in induction and promotion of liver damage progression, in addition to direct injury resulting from different causal agents. Bacterial overgrowth, immune dysfunction, alteration of the luminal factors, and altered intestinal permeability are all involved in the pathogenesis of complications of liver cirrhosis, such as infections, hepatic encephalopathy, spontaneous bacterial peritonitis, and renal failure. Probiotics have been suggested as a useful integrative treatment of different types of chronic liver damage, for their ability to augment intestinal barrier function and prevent bacterial translocation. This review summarizes the main literature findings about the relationships between gut microbiota and chronic liver disease, both in the pathogenesis and in the treatment by probiotics of the liver damage.

Chronic ethanol induces inhibition of antigen-specific CD8+ but not CD4+ immunodominant T cell responses following Listeria monocytogenes inoculation

Chronic ethanol consumption results in immunodeficiency. Previous work with chronic ethanol-fed mice has shown reduced splenic weight and cellularity, including reduced numbers of CD8+ T cells. However, antigen-specific CD8+ and CD4+ T cell responses in chronic ethanol-fed mice have been studied relatively little. We have used an attenuated Listeria monocytogenes strain DPL 1942 (LM DeltaactA) to inoculate mice and subsequently used CD4+ and CD8+ immunodominant peptides of LM to measure the CD4+ and CD8+ T cell responses after chronic ethanol exposure. We found no major differences between control and ethanol-fed mice in the kinetics and persistence of antigen-specific CD4+ T cells in response to an immunodominant LM peptide, as measured by intracellular IFN-gamma staining. In contrast to CD4+ responses, three methods of in vitro antigen presentation indicated that the primary response of CD8+ T cells to several different epitopes was reduced significantly in mice chronically fed ethanol. Antigen-specific CD8+ T cells were also reduced in chronic ethanol-fed mice during the contraction phase of the primary response, and memory cells evaluated at 29 and 60 days after inoculation were reduced significantly. BrdU proliferation assays showed that in vivo proliferation of CD8+ T cells was reduced in ethanol-fed mice, and IL-2-dependent in vitro proliferation of naive CD8+ T cells was also reduced. In conclusion, these results suggest that antigen-specific CD4+ T cell responses to LM are affected little by chronic ethanol consumption; however, antigen-specific CD8+ T cell responses are reduced significantly, as are in vivo and in vitro proliferation. The reduction of antigen-specific CD8+ T cells may contribute strongly to the immunodeficiency caused by ethanol abuse.

Alcoholic pancreatitis: mechanisms of viral infections as cofactors in the development of acute and chronic pancreatitis and fibrosis

Acute and chronic pancreatitis is associated with alcohol abuse, but symptomatic pancreatitis develops in only a small proportion of persons (10-20%) who abuse alcohol. This apparent paradox has led to the notion that additional cofactors are involved in the development of alcoholic pancreatitis. Potential cofactors, such as diet and smoking, have been suggested, but there are no compelling epidemiologic data to support this idea. A number of viruses and some bacteria have been shown to infect the pancreas and produce pancreatitis. One important mediator of pancreatitis in persons with a compromised immune system is a viral infection. The increased susceptibility of immunocompromised persons to viral pancreatitis led to the hypothesis, described in this paper, that the well-known immunosuppression associated with alcohol abuse would result in a more severe viral pancreatitis in mice, which are provided ethanol, than in control animals. To test this hypothesis, C57BL/6 mice were infected with a virulent strain of coxsackievirus B3, which preferentially induces pancreatitis, or with a strain that is naturally avirulent. The study findings presented in this paper show that ethanol consumption alone does not produce pancreas damage but results in a more severe and prolonged pancreatitis after infection with a virulent virus and interestingly, after infection with the avirulent strain of virus. This was associated with an increased number of viruses in the pancreas and spleen, which correlated with decreased humoral immune responses to the virus.

Cutaneous signs as a presenting manifestation of alcohol excess

We describe three patients who presented with a total of four episodes of an inflammatory dermatosis associated with alcohol abuse. In each case, the rash had similar characteristic features. The patients responded promptly to emollients and topical steroids but not to zinc replacement therapy. Other nutrient deficiencies were not identified. In addition, long-term remission seemed to be dependent on a reduction in alcohol consumption. We postulate that this is a separate cutaneous manifestation of chronic alcohol misuse and that this syndrome may be more common than previously thought.

The effects of alcohol on immunity and bacterial infection in the lung

When faced with invading pathogens that can lead to infection, patients must mount an effective and appropriate immune response. Altered immune function in patients who abuse alcohol has long been described in the medical literature. The alcohol-consuming host is particularly prone to infections in the lung, including bacterial pneumonia and tuberculosis. Over the last several decades, there has been increased interest in the immune mechanisms that underlie the increased risk of infection observed in this population. This article will review the basic immunology involved in the host response to an infection and then describe how alcohol disrupts many of these immune mechanisms. It will further provide an overview of lung infections which have been linked to alcohol abuse, and finally, it will address the evolving therapeutic approaches of the immune system that are being advanced to assist in caring for immunosuppressed hosts.

Drug abuse, innate immunity and hepatitis C virus

Since its discovery in 1989, hepatitis C virus (HCV) has become a major public health problem. HCV chronically infects an estimated 170 million people worldwide. The seroprevalence of anti-HCV antibody in the United States has been estimated at 1.8%, which corresponds to approximately 4 million people. HCV is the most common chronic blood borne infection in the United States, and the leading cause of liver transplantation in developed countries. Injection drug use is the dominant mode of HCV transmission and accounts for up to 90% of current infections. Opiates and other drug abuse, such as alcohol, have been implicated as cofactors in the pathogenesis of HCV disease. Injection drug use has been the most common risk factor identified in alcoholics with HCV infection. Both opiates and alcohol contribute significantly to morbidity and mortality from HCV disease. These drugs most likely act synergistically to promote the development and progression of HCV disease. However, there is limited information available concerning the interaction of the drug abuse with the host cell innate immunity against HCV infection, which is a major barrier to fundamental understanding of the immunopathogenesis of HCV disease. Therefore, defining the role of the drug abuse in the development of chronic HCV infection is of crucial importance and should provide practical guidance toward the reduction of risk factors that interfere with therapeutic approaches for HCV infection and disease. This review paper focuses on the interplay between drug abuse (opiates and alcohol), innate immunity and HCV in the context of the development of HCV disease.

Effect of alcohol consumption on the gut

Consumption of large quantities of alcoholic beverages leads to disturbances in the intestinal absorption of nutrients including several vitamins. The inhibition of the absorption of sodium and water caused by alcohol contributes to the tendency in alcoholics to develop diarrhoea. Excessive alcohol consumption (even a single episode) can result in duodenal erosions and bleeding and mucosal injury in the upper jejunum. An increased prevalence for bacterial overgrowth in the small intestine may contribute to functional and/or morphological abnormalities of this part of the gut and also to non-specific abdominal complaints in alcoholics. The mucosal damage caused by alcohol increases the permeability of the gut to macromolecules. This facilitates the translocation of endotoxin and other bacterial toxins from the gut lumen to the portal blood, thereby increasing the liver's exposure to these toxins and, consequently, the risk of liver injury. The results of recent experimental studies support the assumption that alcohol significantly modulates the mucosal immune system of the gut.

Alcohol consumption is associated with alterations in macrophage responses to interferon-gamma and infection by Salmonella typhimurium

Abuse of ethanol (EtOH) by human beings and administration of EtOH to experimental animals has been shown to be associated with a suppression of the immune system. Consumption of EtOH has also been associated with an increased incidence and severity of infections of human beings and experimental animals, which has been attributed to the immunosuppression associated with EtOH consumption. It has been shown that EtOH also affects the function of macrophages (MØ), which are important effector cells in the innate and adaptive immune responses to infectious agents. The present studies were designed to investigate the effects of EtOH on MØ function with an animal model of EtOH consumption. The experiments reported in this paper were done with inflammatory MØ and were designed to determine the effects of EtOH on the ability of inflammatory MØ to respond to interferon-gamma (IFN-gamma) to control the intracellular growth of Salmonella typhimurium, as well as the production of proinflammatory cytokines and nitric oxide. The ability of MØ from EtOH-fed mice to respond to bacterial endotoxin (lipopolysaccharide (LPS)) and IFN-gamma was also evaluated. MØ isolated from EtOH-fed mice did not respond as well to IFN-gamma as MØ isolated from control mice as measured by control of S. typhimurium, as well as tumor necrosis factor (TNF) and nitric oxide production. Interleukin (IL)-6 production was not affected. Activation of MØ from EtOH-fed mice with LPS and IFN-gamma produced levels of nitric oxide and TNF only slightly less than the levels seen in MØ from control mice, but a significant decrease in IL-6 was seen when MØ from EtOH-fed mice were stimulated with this combination. Flow cytometric analyses showed that IFN-gamma receptor expression was not affected by EtOH. Together the data presented in this paper show that consumption of EtOH is associated with changes in inflammatory MØ responses to IFN-gamma.

Difference in quasispecies of the hypervariable region 1 of hepatitis C virus between alcoholic and non-alcoholic patients

BACKGROUND

Habitual alcohol intake is known to aggravate the clinical outcome of hepatitis C virus (HCV)-related chronic liver diseases and to increase the risk of hepatocellular carcinoma.

METHODS

To investigate the possible mechanism of these effects by alcohol, we examined 31 cases of HCV-related chronic liver diseases of which 17 cases were drinking just before admission and the remaining 14 cases were non-drinkers. The studied cases included 18 patients with chronic hepatitis, six with liver cirrhosis and seven with hepatocellular carcinoma. The quasispecies of the hypervariable region 1 of the HCV genome were analyzed by using polymerase chain reaction single strand conformation polymorphism (PCR-SSCP). Hepatitis C virus viral load was quantitated by using multicyclic PCR after reverse transcription of the 5' non-coding region of the genome.

RESULTS

The mean PCR-SSCP band number that reflected the quasispecies complexity in hypervariable region 1 was more significantly increased in alcoholics than in non-alcoholics (5.5 +/- 1.4 vs 3.9 +/- 1.1, P< 0.01). The significant increase in alcoholics remained, even if the cases were restricted to males (P < 0.01), to HCV genotype 1b (P < 0.05) or to chronic hepatitis (P < 0.05). The HCV viral load was not statistically different between alcoholic and non-alcoholic HCV-related chronic liver diseases (5.02 x 10(6) +/- 5.16 x 10(6) copies/mL vs 9.00 x 10(7) +/- 2.75 x 10(8) copies/mL, P = 0.28). Mutation events seemed to occur randomly when amino acid sequences of hypervariable region 1 were compared between four drinkers and four non-drinkers.

CONCLUSIONS

The enhanced quasispecies complexity in hypervariable region 1 of HCV in alcoholics may be the main cause of more progressive HCV-related chronic liver diseases, and may provide the disease the resistance against any therapeutic modalities including interferon.

Effect of adrenalectomy on ethanol-associated changes in lymphocyte cell numbers and subpopulations in thymus, spleen, and gut-associated lymphoid tissues

Consumption of ethanol (ETOH) by experimental animals and human beings is associated with elevated serum levels of corticosteroids. One of the most robust findings associated with ETOH consumption is a loss of lymphocytes from thymus and spleen, as well as from peripheral lymphoid organs to include mesenteric lymph nodes and Peyer's patches, which are lymphoid organs associated with the gastrointestinal tract. To study the role of corticosteroids in loss of cells from thymus, spleen, and gut-associated lymphoid organs, adrenalectomized (ADX) or intact C57Bl/6 mice were fed a liquid diet containing ETOH (to supply 36% of calories as ETOH) or an isocaloric control diet with a pair-feeding protocol. Loss of lymphocytes from all lymphoid organs was associated closely with serum corticosterone levels in both ETOH-fed and pair-fed groups. ETOH-fed ADX animals showed much less cell loss than did ETOH-fed intact animals. However, there was still an association between ETOH consumption and cell loss when cell loss in ETOH-fed ADX animals was compared with that in ADX pair-fed and ADX chow-fed groups. In both intact and ADX animals ETOH consumption was associated with a loss of immature (CD4(+) and CD8(+)) cells from the thymus. These data lead to the suggestion that corticosteroids are responsible for most of the cell loss from thymus, spleen, mesenteric lymph nodes, and Peyer's patches in association with ETOH consumption. Some cell loss, however, is independent of corticosteroids. The data presented here also support the suggestion that cell loss from lymphoid organs could be the result of nutritional factors.

Ethanol impairs major histocompatibility complex (MHC) class II molecule-mediated but not MHC class I molecule-mediated T cell response in alcohol-consuming mice

The goal of this study was to determine whether alcohol affects alloantigen-induced proliferative and cytolytic activity of T cells in mice, and whether the altered immune response was in part due to a defect of IL-2 activity. The ability of spleen cells from individual alcohol-consuming C57BL/6 mice to generate allo-specific mixed lymphocyte response (MLR) and cytotoxic T lymphocyte (CTL) was compared to that of mice fed on an isocaloric maltose diet and regular diet. Allospecific MLR and CTL were generated by sensitizing spleen cells of C57BL/6 mice against spleen cells from BALB/c mice, and the allo-specific CTL activity was determined by the ability of the CTL to kill 51Cr-labeled P815 mastocytoma target cells. Our results showed that the allo-specific MLR of the responder cells from alcohol-consuming mice was significantly reduced (40% reduction, p<0.0 1), and the addition of exogenous interleukin 2 (IL-2) could not reverse the suppression of MLR induced by ethanol. However, our results clearly showed that ethanol has little suppressive effect on allo-reactive CTL of alcohol-consuming mice as compared to the alloreactivity of the control mice (P>0.05). Finally, we also demonstrated that ethanol did not impair the alloantigen-induced IL-2 production in the mixed lymphocyte cultures (P>0.1).

Isotonic ethanol inhibits the generation of superoxide anion in neutrophils by inducing cell expansion

The effects of ethanol on the production of oxygen-derived free radicals by neutrophils are controversial. Osmolarity-mediated alteration of cell volume appears to be an important mechanism for regulating neutrophil activity. We investigated in neutrophils from healthy volunteers the effect of isotonic/hypertonic ethanol on both chemiluminescence amplified by a Cypridina luciferin analog in response to N-formyl-Met-Lue-Phe and cell volume measured with a Coulter counter. Both isotonic and hypertonic ethanol significantly decreased chemiluminescence in a dose-dependent manner. Isotonic ethanol produced a greater magnitude of inhibition than hypertonic ethanol (P<0.01). Another permeable molecule, urea, and hypotonic solution had the same effects on chemiluminescence. Isotonic and hypertonic ethanol caused a prompt cell expansion and shrinking, respectively. On the other hand, isotonic sucrose, an impermeable molecule, was ineffective in both chemiluminescence and cell volume changes. These data suggest that isotonic ethanol inhibits the superoxide anion production by inducing cell expansion probably due to increased intracellular osmotic pressure caused by rapid ethanol permeation through the plasmalemma. This impaired neutrophil function may, in some part, contribute to the susceptibility to infection in alcoholics.

Ethanol-induced expression of cytokines in a first-trimester trophoblast cell line

OBJECTIVES

Altered cytokine expression at the fetoplacental interface may be a potential mechanism for the development of fetal immune dysfunction in children with fetal alcohol syndrome. This study was conducted to determine whether first-trimester trophoblasts respond to ethanol exposure by the induction of specific cytokines.

STUDY DESIGN

HTR-8/SVneo trophoblast cells were cultured in vitro in the presence of either ethanol (0.5% [vol/vol]), lipopolysaccharide (1 microg/mL), or ethanol and lipopolysaccharide. Expression of granulocyte colony-stimulating factor, regulated on activation normal T cell expressed and secreted, and interleukin-6 was examined by Northern analysis and enzyme-linked immunosorbent assay.

RESULTS

Culture in the presence of ethanol, lipopolysaccharide, or lipopolysaccharide and ethanol resulted in the increased transcription and secretion of granulocyte colony-stimulating factor, regulated on activation normal T cell expressed and secreted, and interleukin-6 at significantly greater levels (P < .01) than control cultures.

CONCLUSIONS

Human first-trimester trophoblasts express high levels of cytokines when cultured in the presence of ethanol. Trophoblasts may therefore be an important exogenous source of cytokines for the fetus, and altered cytokine levels during early gestation may have an adverse effect on the development of the fetal immune system.

Alveolar macrophage release of tumor necrosis factor-alpha in chronic alcoholics without liver disease

Alcohol is an immunosuppressive drug, and chronic abuse has been associated with increased susceptibility to a variety of infections, including bacterial pneumonia and tuberculosis. Alveolar macrophages are the resident phagocytes of the lung and play a central role in lung host defenses against infection ranging from direct antibacterial activity to the release of proinflammatory cytokines such as tumor necrosis factor-alpha (TNFalpha). TNFalpha, in particular, plays a key role in the development of the early inflammatory response. In this study, we investigated the effects of chronic alcohol consumption on alveolar macrophage release of TNFalpha in vitro. We prospectively studied lipopolysaccharide (LPS)-stimulated release of TNFalpha from alveolar macrophages obtained from bronchoalveolar lavage fluid (BALF) in 22 alcoholic (18 smokers, 4 nonsmokers) and 7 nondrinking healthy volunteers (3 smokers, 4 nonsmokers). The total number of cells recovered by bronchoalveolar lavage (BAL) and their differential distribution were not significantly different in alcoholics versus controls (43 +/- 8 x 10(6) and 39 +/- 13 x 10(6), respectively). However, the total number of cells recovered from BALF was significantly higher in smokers (51 +/- 8 x 10(6)) than in nonsmokers (19 +/- 5 x 10(6)). Spontaneous (basal) release of TNFalpha by alveolar macrophages was the same in alcoholics and controls. In contrast, LPS-stimulated release of TNFalpha was significantly suppressed in alcoholics compared with that of controls (1343 +/- 271 vs. 3806 +/- 926 U TNF/ml/10(6) cells, respectively, p < 0.015). When controlled for smoking, LPS-stimulated TNFalpha production was suppressed in alcoholic nonsmokers (563 +/- 413 U TNF/ml/10(6)) compared with control nonsmokers (5113 +/- 1264 U TNF/ml/10(6)). LPS-stimulated TNFalpha production was also less in control smokers (2063 +/- 386 U TNF/ml/10(6) cells) than in control nonsmokers (5113 +/- 1264 U TNF/ml/10(6) cells). There was no difference in TNFalpha production between smoking alcoholics and smoking control subjects. We conclude that chronic alcohol consumption significantly suppresses LPS-stimulated alveolar macrophage production of TNFalpha. This effect is obscured if the subject also smokes. Because TNFalpha production is an important element in host defense, this may explain, in part, the susceptibility of chronic alcohol abusers to a variety of infections.

Hepatic haemodynamics and reticuloendothelial function in the rat in response to chronic ethanol administration

This study investigated the effects of chronic ethanol intake on hepatic haemodynamics and reticuloendothelial system function in the rat. Comparisons were also made with blood flow to pancreas, kidney, spleen, lung and skin. Male Wistar rats, approximately 0.15 kg initial body weight, were fed a diet containing 35% of the total calories as ethanol. Controls were pair-fed identical amounts of the same diet in which ethanol was replaced by isocaloric glucose. The hepatic perfusion index and reticuloendothelial function was determined with [(99m) Tc]-labelled sulphur colloid [(99m) Tc]-SC) and blood flow with radiolabelled microspheres under anaesthesia. After 4-5 weeks the weights of liver and skin of alcohol fed rats decreased by 10% (p= 0.040) and 23% (p= 0.024), respectively, compared to controls and there was a small increase in kidney weight (15%, p = 0.001). Blood flow to liver, pancreas, kidney, spleen, lung and skin was not altered significantly by chronic alcohol administration, irrespective of whether the data were expressed as a percentage of cardiac output, blood flow per minute per organ or blood flow per minute per g tissue weight (p > 0.113 in all instances). However, there was a significant increase in splenic reticuloendothelial system activity (+ 121%, p = 0.018). Hepatic reticuloendothelial system activity was also increased (+ 22%, p = 0.061). Chronic alcohol administration resulted in significant increases in portal pressure (+ 55%, p = 0.042) and portal venous resistance (+ 66%, p = 0.001), but portal venous inflow and hepatic perfusion index were not altered compared to controls The results of this study indicated that chronic alcohol administration did not alter visceral blood flow significantly, but did increase portal pressure, portal vascular resistance and reticuloendothelial system activity.

Naltrexone prevents ethanol-induced changes in rat thymus

Ethanol is known to suppress the immune response, but the underlying mechanism accounting for the immunosuppression is not clearly elucidated yet. The purpose of this study was to investigate the effect of a single dose of ethanol on relative proportion of the four major rat thymocyte subsets and possible mechanism of its action. To this end, adult female AO rats were treated with: a) ethanol (2 or 4 g/kg, i.p.), b) naltrexone (5 mg/kg, i.p.) followed 45 min later by ethanol (2 or 4 g/kg, i.p.), c) naltrexone (5 mg/kg, i.p.), or d) only saline. Twenty hours later the rats were sacrificed and the proportion of the four major thymocyte populations defined by expression of CD4 and CD8 molecules was analyzed. Flow cytometric analysis revealed that ethanol evoked a decrease in the percentage of double-positive CD4+CD8+ thymocytes followed by a proportional increase in the percentage of single-positive CD4+CD8- cells. Naltrexone pretreatment prevented the ethanol-induced alterations in thymocyte subsets. The results clearly indicate that ethanol affects the process of intrathymic T-cell maturation. It seems that this effect might be mediated by an opioid-dependent mechanism.

Ethanol ingestion inhibits cell-mediated immune responses of unprimed T-cell receptor transgenic mice

This paper introduces a transgenic (Tg) mouse in which the majority of the CD4-bearing T cells have T-cell receptors that react with ovalbumin (OVA) as a model for ethanol research. Although these Tg animals were bred onto the BALB/c genetic background, a strain generally considered to be nonpreferring in ethanol consumption, we determined that BALB/c mice would consume an ethanol-containing liquid diet, without significant mortality, and assessed alteration of specific immune responses. BALB/c, C57BL/6 (B6), or (BALB/c x C57BL/6)F-1 hybrid (CB6F1) mice were fed LED containing 35, 30, 25, or 20% ethanol-derived calories. Significant mortality (> 40%) was seen only in BALB/c and pronounced weight loss was seen in BALB/c, B6, CB6F1 mice when they were fed the diet containing the greatest ethanol concentration (LED35). Diets containing lesser amounts of ethanol did not cause mortality. Liquid diets containing > or = 30% ethanol-derived calories significantly impaired the chicken gamma-globulin-specific delayed hypersensitivity responses in BALB/c, B6, and CB6F1mice without significantly affecting the humoral immune response to sheep red blood cells. We show that immunization of the Tg mice is not required for the development of a vigorous "delayed hypersensitivity" response to OVA or the I-Ad-restricted peptide OVA323-339 in mice fed standard solid lab chow or liquid control diet. In marked contrast, OVA Tg mice fed ethanol show a profound inhibition of this immune response, indicating that ethanol-induced inhibition of cell-mediated immunity occurs independently of antigen priming.

Alcohol inhibits lipopolysaccharide-induced tumor necrosis factor alpha gene expression by peripheral blood mononuclear cells as measured by reverse transcriptase PCR in situ hybridization

We recently showed that alcohol significantly suppressed lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNF-alpha) production by whole blood and total mononuclear cells from healthy subjects as measured by bioassay. In the current study, we further examined the effect of alcohol on LPS-induced TNF-alpha gene expression by semiquantitative solution PCR and in situ reverse transcriptase PCR (RT-PCR) hybridization methods. Peripheral blood mononuclear cells were cultured with LPS (10 micrograms/ml) for 4 to 8 h with or without different concentrations of ethanol (0.1, 0.2, and 0.3% [vol/vol]). Total RNA from treated and untreated cultures was extracted and used for solution PCR analysis. Treated and untreated cells were subjected to both conventional in situ hybridization and RT-PCR in situ hybridization. In solution RT-PCR in vitro analysis, alcohol significantly suppressed TNF-specific message. In conventional in situ hybridization, the effect of alcohol on TNF-alpha gene expression was poorly detected. However, when cells were subjected to RT-PCR prior to in situ hybridization, cells treated with alcohol significantly suppressed expression of the message for TNF-alpha. These studies confirm our earlier finding that alcohol suppressed the production of TNF-alpha by LPS-induced whole blood cells and peripheral blood mononuclear cells. Furthermore, these studies also demonstrate that the RT-PCR in situ technique is a powerful tool for detecting and amplifying specific genes in whole cells when limited numbers of cells are available for RNA extraction.

Effects of exogenous cytokines on the ethanol-mediated suppression of murine thymocyte proliferation

Although attempts have been made to assess the effect of ethanol on murine thymocyte proliferation, the mechanism which accounts for the immunosuppressive effect of ethanol on the thymocyte proliferation has not been elucidated. Thus, a mouse model was used to determine (1) whether there is a similarity in the effect of ethanol exposure in vitro and in vivo on the proliferative response of thymocytes to phytohemagglutinin (PHA), (2) whether ethanol exposure affects the responsiveness of thymocytes to exogenous interleukin (IL)-1 and IL-2, and (3) whether ethanol affects IL-1 production by peritoneal macrophages. We found that the proliferative response of thymocytes from mice fed on an ethanol-containing diet was significantly inhibited (P < 0.05) compared to that in mice fed on maltose or standard diets. We also observed that low concentrations of ethanol (12.5 mM) appeared to enhance the mitogenic response of thymocytes to PHA, but the response was not significantly greater than that of controls (P > 0.05). Ethanol at higher concentrations (25-100 mM) significantly suppressed the mitogenic response of thymocytes to PHA (P < 0.05) in a dose-dependent manner. Our data also revealed that (1) ethanol did not significantly suppress IL-1 secretion by adherent macrophages stimulated by LPS, and (2) the addition of exogenous IL-1 was insufficient to restore full responsiveness in thymocytes from ethanol-fed mice. Taken together, these results suggest that the suppressive effect of ethanol on thymocyte proliferation is not mediated by insufficient IL-1. Finally, we present novel evidence that addition of exogenous IL-2 completely restores the impaired proliferative response of thymocytes from ethanol-fed mice to control levels. In summary, our results demonstrate that ethanol inhibits thymocyte proliferation in response to PHA, and that the inhibition is not due to insufficient IL-1. We also report that addition of exogenous IL-2 is sufficient to restore full proliferative capacity to thymocytes from ethanol-fed mice.

Alcohol modulation of human normal T-cell activation, maturation, and migration

We are interested in the characterization of the effects of alcohol on human T-cell activation, maturation, and migration, because this cell population is crucial in the initiation, regulation, and propagation of cellular immunity. We and others have described the effects of both acute and chronic exposure of human immune cells to ethanol (EtOH) in vitro. Herein, we briefly, review these reports and expand this body of literature with the inclusion of new data recently obtained in our laboratory. We confirm the blunting effects of EtOH on the production of interleukin-2 and mitogen proliferative response following T-cell mitogen stimulation, and on the expression of membrane markers of activation. We show that EtOH significantly alters the expression of the CD4 cell-associated marker of activation, CD26. We report the effect of EtOH on the expression of the homing receptor CD62L by CD4+ cells, and on their ability to adhere by a CD18-mediated process to a defined cellular substratum. Furthermore, we demonstrate the effects of EtOH and EtOH and beta-endorphin pretreatment on the activation of CD4+ lymphocytes endowed with the homing receptor CD62L.

Ethanol-induced depletion of lymphocytes from the mesenteric lymph nodes of C57B1/6 mice is associated with RNA but not DNA degradation

The effects of ethanol (EtOH) consumption by adult female C57B1/6 mice on lymphocyte populations of the mesenteric lymph nodes (MLNs) were determined by feeding mice with the Lieber-DeCarli liquid diet by a pair-feeding paradigm. Histological analysis of the MLNs of EtOH-fed mice showed a progressive loss of lymphocytes from the medullary regions at 3, 5, and 7 days after initiation of the EtOH diet. The stromal cells in the medullary region also demonstrated a progressive alteration in stellate morphological features at times corresponding to those of loss of lymphocytes from this region. Microscopic evaluation of the follicle regions of MLNs obtained from mice fed an EtOH-containing diet showed no appreciable alterations in morphological characteristics. The number of tingible body macrophages in the germinal centers of the follicles, however, was increased after 3 days of EtOH diet feeding and declined progressively after this time. Flow cytometric analysis of isolated lymphocytes showed a depletion of both T and B cell populations from the MLNs. In contrast to B cells, however, T cells were depleted through 7 days of EtOH diet feeding. Total RNA isolated from the MLNs of mice consuming the EtOH-containing diet was progressively degraded. No degradation of DNA was observed. These study results establish that continuous consumption of dietary EtOH adversely affects the cellularity of MLN, resulting in a progressive loss of lymphocytes that is associated with degradation of total RNA.

Effects of ethanol on cellular immunity to facultative intracellular bacteria

Alcohol abuse has been associated with an increase in infectious diseases caused by pathogenic and opportunistic microorganisms. Study results obtained from this laboratory and other laboratories have shown that consumption of large amounts of ethanol is associated with numerous changes in the immune system. The purpose of this article is to report findings obtained from this laboratory, as well as review those obtained from other laboratories, from experiments designed to evaluate the effects of ethanol on various components of antimicrobial host-defense mechanisms. The effects of ethanol on various aspects of immunity obtained with the use of in vivo and in vitro model systems are reviewed as they pertain to antimicrobial defenses. All current data would support the suggestion that ethanol affects both the development of an antigen-specific immune response and the effector mechanisms of the cellular immune response. Findings obtained from animal models show that ethanol prevents the formation of granulomas in infected tissues, perhaps by inhibiting the response of macrophages to T-cell cytokines. Data obtained from this laboratory also support the suggestion that the inability of the immune system to control the intracellular growth of microorganisms results in an exaggerated inflammatory response that is responsible for at least a part of the tissue damage.

Selective inhibition by alcohol and cortisol of natural killer cell activity of lymphocytes from cord blood

1. The immunosuppressive effects of drugs such as alcohol or hormones such as cortisol may be age-related. To test this hypothesis, the authors investigated the in vitro effects of ethanol (EtOH) and cortisol on Natural Killer (NK) cell activity of lymphocytes from normal cord blood in comparison with that of lymphocytes from normal adult peripheral blood. 2. K562, an erythroleukemia cell line, was used as a target in a 4 hr 51Cr release assay. 3. Ethanol at 0.3% (V/V) and cortisol at 0.05, 0.1 and 0.2 microgram/ml concentrations, added directly to a mixture of effector and target cells significantly suppressed the NK activity of cord blood lymphocytes in a dose dependent fashion, whereas similar concentrations of either EtOH or cortisol did not manifest significant immunoregulatory effects on NK cell activity of normal adult lymphocytes. 4. Pre-treatment of the target with either EtOH or cortisol for 4 hours did not affect cytotoxicity. Inhibition of cytotoxicity was also not due to direct toxicity of effector cells because lymphocytes treated with either EtOH or cortisol showed normal 51Cr release and their viability was comparable to that of untreated control cells. 5. This suggests a selective inhibitory effect of EtOH and cortisol on NK activity of neonatal lymphocytes that may be of clinical significance.

Suppression of tumor necrosis factor production by alcohol in lipopolysaccharide-stimulated culture

Many studies have shown that alcohol consumption is associated with alteration in immune responses and increased incidence of infection in the host. Tumor necrosis factor (TNF) is a potent soluble mediator of immunoregulation and inflammation, and plays a very important role in host's defenses against infection and tumor. We propose that one of the mechanisms of alcohol-mediated immunosuppression may be due to a defect in the synthesis and release of the TNF. To determine this, we studied the direct effect of alcohol on lipopolysaccharide (LPS)-induced TNF production by whole blood and total mononuclear cell from normal subjects. Aliquots of blood samples (1 ml) or ficoll-hypaque separated total mononuclear cells (1 x 10(6)/ml) were cultured with different concentrations of either ethanol or acetaldehyde in the presence or absence of LPS for 4 hr at 37 degrees C. Plasma samples and culture supernatants were assayed for TNF levels in a bioassay using a TNF-sensitive WEHI 164 subclone 13 cell line. LPS at 10 micrograms/ml produced a maximal level of TNF compared with lower (1 micrograms/ml) or higher concentration (50 micrograms/ml) of LPS. Kinetics studies showed that an incubation time of 4 hr with LPS produced a maximum level of TNF production by blood. Alcohol, as low as 0.1% concentration, produced significant suppression of LPS-induced TNF production by whole blood, whereas alcohol at 0.2 and 0.3% concentrations were required to produce a significant suppression of TNF production by separated mononuclear cells. Anti-TNF-alpha antibodies significantly neutralized the LPS-induced TNF that suggests that blood monocytes may be the primary source of TNF production.(ABSTRACT TRUNCATED AT 250 WORDS)

Selective effect of alcohol on cellular immune responses of lymphocytes from AIDS patients

In this study we examined the in vitro effects of alcohol on the proliferative responses of lymphocytes from healthy donors and AIDS patients to a recombinant fusion peptide, env-gag, corresponding to portions of the gp41 envelope (env) and internal core (gag) proteins of HIV. The effects of alcohol (ETOH) on the natural killer (NK) cell activities of lymphocytes from healthy donors and patients with AIDS were also investigated. Peripheral blood mononuclear cells from both normal donors and AIDS patients produced significant levels of lymphocyte proliferative responses to the HIV env-gag peptide; however, these responses were significantly higher in patients with AIDS, showing the specificity of the response. The env-gag-induced proliferative responses of lymphocytes from normal subjects were significantly suppressed when cultures contained only higher levels of ETOH (0.2% and 0.3%), whereas ETOH even at a lower level (0.1%) produced significant suppression of the env-gag-induced proliferation of lymphocytes only from AIDS patients. Direct addition of ETOH at concentrations of 0.1%, 0.2%, and 0.3% to cultures of lymphocytes from normal donors and NK target cells did not produce significant suppression of NK cell activities. However, ETOH at concentrations of 0.2% and 0.3% significantly suppressed the NK activities of lymphocytes from AIDS patients, and the suppressive effect was observed at all E:T cell ratios examined. Control peptide from the Escherichia coli expression vector did not produce any significant effect on lymphocyte proliferative responses or NK activity of both normal donors and AIDS patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Flow cytometric analysis of lymphocyte subsets of mice maintained on an ethanol-containing liquid diet

Alcoholic patients often have impaired immune function, yet little is known about the precise mechanism(s) of this impairment. We have previously shown that ethanol consumption by mice alters copolymer-specific humoral and cellular immune responses. In this study, we asked whether alcohol consumption by mice would phenotypically alter lymphocyte populations. Female C57BL/6 mice were fed a nutritionally complete liquid diet containing 35% ethanol-derived calories for up to 8 days. As controls, mice either were fed a liquid control diet that isocalorically substitutes sucrose for ethanol or remained on a standard solid diet and water ad libitum. Although mice fed ethanol-containing liquid or pair-fed control liquid diets have decreased numbers of spleen cells compared with solid diet controls, only the ethanol-containing diet allowed normally nonresponder C57BL/6 spleen cells to make antibody responses to the poly(Glu50Tyr50) synthetic copolymer antigen. Flow cytometric analysis of splenic lymphocyte populations of mice on the ethanol-containing diet shows an increase in the relative proportion of T-lymphocytes as compared with mice on either solid or liquid control diets. No such change is seen for either B-cell or natural killer cell populations in these same mice. Both liquid control and liquid ethanol diets caused a slight decrease in the CD4:CD8 ratios of splenic T-lymphocytes. We see the relative percentage of T-cells bearing the alpha beta T-cell receptor (TcR) increases in the spleens of liquid ethanol diet mice; a smaller increase TcR alpha beta usage is seen in the spleens of liquid control mice, compared with solid diet mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Fine T-cell subsets in alcoholics as determined by the expression of L-selectin, leukocyte common antigen, and beta-integrin

Alcoholics admitted to the hospital solely for detoxication have been studied by flow cytometry to evaluate changes in the surface markers of peripheral blood leukocytes. As we have shown previously, such patients have an elevated percentage of CD8hi lymphocytes that are HLA DR+; we now demonstrate that they also have striking alterations in the quantitative relationships of the fine T-cell subsets. Both CD4+ and CD8hi lymphocytes have a sharply reduced percentage of the L-selectin+ CD45RA+ subset, increased percentages of the CD45RA- subsets, and several other fine subset alterations. The fine subset profile suggests, according to current correlations of phenotype and function, that both CD4+ suppressor inducer and CD4-dependent CD8+ suppressor effector cells are reduced, whereas other subsets, including CD8+ CTL or their precursors, are increased in relative percentages. Some of the phenotypic changes are reversible over the several days following withdrawal. In other results, the percentage of CD8hi lymphocytes epxressing CD11b (beta-integrin) is shown to be reciprocal with the percentage expressing L-selectin both in normals and alcoholics. However, the regression function of CD11b vs. L-selectin on CD8hi cells is different for the alcoholics than for the normals, indicating an abnormality in the regulation of the expression of these two adhesion markers. Taken together, this abnormality of adhesion molecules and the fine subset alterations previously described indicate widespread changes in the peripheral lymphocytes of currently drinking alcoholics. These changes suggest functional deficiencies that may include alterations of lymphocyte traffic and other adhesion-dependent functions, and a shift in the balance of regulatory interactions.

Effect of postnatal ethanol exposure on expression of differentiation antigens of murine splenic lymphocytes

Ethanol is a recognized immunosuppressive agent in the chronic alcoholic. However, the effects of ethanol exposure on the developing immune system have not been extensively investigated. This study evaluated the effects of early postnatal ethanol exposure, via breast milk, on splenic lymphocyte differentiation antigen expression in offspring reared by ethanol-fed mice. Maternal mice were fed a liquid diet containing 20% ethanol-derived calories during pregnancy (E-P), pregnancy and lactation (E-PL), or lactation (E-L). Ad libitum-fed (C) and pair-fed (PF) control groups, fed a control liquid diet, were included. Expression of differentiation antigens on splenic lymphocytes from 21-day-old offspring reared by females in 1 of the 3 ethanol exposure conditions was evaluated by flow cytometry. Offspring reared by E-P females had similar numbers of splenic lymphocytes as offspring reared by C and pair-fed during pregnancy (PF-P) females. In contrast, offspring reared by E-PL and E-L females had fewer splenic lymphocytes than both PF-PL and PF-L (respectively), and C offspring. The number of Thy 1.2+, CD4+, CD8+, and IgG+ (B-cell) splenic lymphocytes was reduced in E-PL and E-L offspring compared with PF and C offspring. E-P offspring had fewer CD4+ and IgG+ splenic lymphocytes than C, but not PF-P, offspring. The percentage of Thy 1.2+ splenic lymphocytes was significantly reduced among E-PL and E-L offspring compared with PF-PL and PF-L (respectively), and C offspring.(ABSTRACT TRUNCATED AT 250 WORDS)

Phenotype of lymphocytes mediating copolymer-specific humoral immunity in ethanol-consuming C57BL/6 mice

Little is known about the mechanisms of impaired immune function in alcoholic patients. We have previously shown that ethanol consumption by mice alters copolymer-specific humoral and cellular immune responses. Does ethanol consumption eliminate suppressor T cells, allowing nonresponder mice to make humoral immune responses to poly(Glu50Tyr50) (GT)? Female C57BL/6 mice were fed a nutritionally complete liquid diet containing 35% ethanol-derived calories for up to 33 days. Control mice were fed an isocaloric control liquid diet or remained on a solid diet and water. Mice fed the ethanol-containing diet made GT-specific plaque-forming cell (PFC) responses, whereas mice fed liquid control or solid diets did not. Lymphocytes from ethanol liquid diet-consuming mice helped splenocytes from either solid or liquid control mice to make a GT-specific PFC response. The cells mediating help were nylon wool nonadherent, CD4-bearing T cells. These findings suggest that ethanol does not eliminate copolymer-specific suppressor cells, but instead alters the functional capability of helper T cells for humoral immune responses.

Effect of isolated portal hypertension on Kupffer cell function

The increased incidence of infection in cirrhotics may in part be attributable to dysfunction of the reticuloendothelial system (RES) in removing pathogens from the circulation. The portosystemic shunting (PSS) that results from portal hypertension in cirrhotics may compromise RES function by allowing enteric pathogens to be shunted away from the Kupffer cells. A well-characterized model of portal hypertension induced by partial portal vein ligation (PVL), in which there is no hepatic parenchymal cell damage, was used. Kupffer cell function is unaltered and the effect of PSS alone on overall RES function can be evaluated. In addition to the usual immunologically inert [99mTc]sulfur colloid, an actual pathogen was also evaluated. PVL and sham-ligated rats were given either [99mTc]sulfur colloid or E. coli via the ileocolic vein. The right femurs, lungs, livers and spleens of the animals receiving 99mTc were excised and the radioactivity counted. The lungs, livers, and spleens of the animals receiving E. coli were liquefied and the bacteria were quantified. For both groups the ratios of 99mTc or E. coli in the lung, spleen, and femur to liver were calculated. PVL rats had significantly more 99mTc in the lung, spleen, and femur than the sham rats. There were also significantly more E. coli in the lungs for PVL rats but no significant difference in the spleen counts. These results imply that even in the absence of Kupffer cell dysfunction, PSS alters reticuloendothelial system function by causing a greater distribution of pathogens to the periphery. This altered distribution may contribute to an increased susceptibility to infection in cirrhotics.

Impaired cytosolic free calcium response in splenic T-cells from mice fed with ethanol-containing diet

Calcium-dependent signal transduction pathways of T-cell proliferation have been extensively studied in the past years. However, little is known about effects of ethanol on the calcium-dependent signal transduction pathway in T-cell proliferation. Thus, a murine model was used to determine effects of ethanol in vivo on T-cell proliferation and the intracellular free calcium concentration [Ca2+]i in response to Concanavalin A (Con A) and recombinant IL2 (rIL2) in T-cells. Splenic cells from young C57BL/6 mice, that had been fed on 3 different diets (ethanol-, maltose substitute- and standard liquid-diet) for 7-8 weeks were tested for their proliferative responses to Con A and rIL2. Concurrently, measurement was also made of [Ca2+]i in the nylon-wool-enriched resting T-cells induced by Con A and in Con-A-activated blast T-cells induced by rIL2. Our results showed that [Ca2+]i increases were seen in the splenic T-cells from three different groups of mice following Con A, but not rIL2 stimulation. However, this increase was much smaller in the splenic T-cells from ethanol-fed mice as compared to mice on maltose- or standard-diet. Furthermore, we also demonstrated that the impaired [Ca2+]i increase was seen in the T-cells of the same ethanol-fed mice having decreased the proliferative response to Con A. This reduced proliferation did not result from the presence of excessive suppressor T-cell activity. Finally, we also demonstrated that both the number of IL2 binding sites/cell and the Kd values of the low- and high-affinity IL2R on the T-cells from ethanol-fed mice were unaltered. Because evidence indicates that (1) a normal level of [Ca2+]i increase is a prerequisite for the production of IL2 by mitogen-stimulated T-cells, and (2) T-cells from ethanol-fed mice have normal capacities to produce IL2 that is the crucial growth factor controlling T-cells to progress through the cell cycle, these lines of evidence taken together with the results of this study suggest that the impairment in [Ca2+]i increases in T-cells from ethanol-fed mice may not be the primary factor contributing to the diminished T-cell proliferation in the same mice.

Increased natural killer cell activity in a model of immunoglobulin A nephropathy secondary to chronic alcohol consumption

We investigated natural killer (NK) cell activity in an animal model of ethanol-induced immunoglobulin A (IgA) nephropathy. Two groups, of 10 rats each, received a continuous intragastric infusion of liquid diet through a permanent cannula for 6 weeks. The alcoholic group was infused additionally with intragastric ethanol, representing from 32% to 40% of the caloric requirement. The group of control rats received an isocaloric diet supplemented with glucose instead of alcohol. IgA nephropathy was observed in all the alcoholic rats but in none of the controls. NK cell activity was investigated in the two groups by measuring the cytotoxicity of spleen cells using the chromium release method. NK cell activity was found to be significantly increased in the alcoholic rats. In view of the known modulation of IgA synthesis by NK cells, we suggest that increased NK cell activity may be a contributing factor to the high levels of circulating IgA seen in IgA nephropathy secondary to chronic alcohol consumption.

Immunosuppression in adult female B6C3F1 mice by chronic exposure to ethanol in a liquid diet

The overall objective of these studies was to characterize the effects of ethanol on the immunocompetence of adult female B6C3F1 mice. To obtain a significant suppression in the antibody response to SRBC, splenocytes from untreated mice had to be directly exposed to concentrations of ethanol from 0.3% to 3.0%, or to acetaldehyde at concentrations greater than 0.03%. We do not believe that these results are consistent with a role by a direct effect by either ethanol or its primary metabolite because these concentrations are higher than what could be obtained as reasonable blood levels. For in vivo exposure, we employed a pair-feeding regimen which was based on a liquid diet containing 5% ethanol (v/v) that provided 36% of the caloric intake as ethanol. Our results indicated that there was a definite temporal relationship to the consequent suppression of the antibody response to SRBC in that no effect was observed after 14 days exposure, and that the magnitude of the suppression increased from 18% after 21 days to 70% after 42 days. We also monitored the liver for histopathology and observed that the ethanol-induced liver damage was restricted to steatosis (fatty liver), which was also manifested with time and which was most pronounced after 42 days exposure. In contrast to our results with the in vivo antibody response, we saw no effect on mitogen-induced proliferation by splenocytes from ethanol-treated mice. These results prompted us to measure in vitro antibody responses by splenocytes from ethanol-treated mice. We saw no suppression of the in vitro antibody responses to SRBC, DNP-Ficoll or LPS after any length of exposure to ethanol, and speculated that the basis for the suppression of the in vivo antibody response was an indirect consequence of exposure. We subsequently determined that when normal splenocytes were cultured in 5% serum from ethanol-exposed mice (42-day group), there was a > 80% suppression relative to the serum from the pair-fed controls. As important controls for these studies, we have demonstrated that there was no difference between the responses of normal lymphocytes cultured in 5% normal mouse serum and in 5% serum taken from the pair-fed restricted controls. A determination of the ethanol content in the serum from ethanol-exposed mice (42-day group) indicated that the amount of ethanol present in these cultures was < 0.003%.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of ethanol on Kupffer cell function

Kupffer cells are resident macrophages in the liver and are important in both local and systemic immune responses. We evaluated the ability of Kupffer cells in vitro to respond to immune stimulation after both acute exposure to ethanol and after long-term ethanol consumption of ethanol. Triplets of female Wistar rats were fed a liquid diet containing 0, 12, or 36% ethanol isocalorically for 112 days. When killed, the Kupffer cells were isolated by collagenase perfusion and adhered to plastic 24-well plates. They were then stimulated with 10 micrograms/ml lipopolysaccharide for 4.5 hr. Synthesis of procoagulant activity (PCA) and tumor necrosis factor (TNF), expressions of macrophage response to immune stimuli, were measured by a one-step clotting assay and L929 cytotoxicity assay, respectively. Within each of the 10 triplets, PCA and TNF levels were normalized and expressed as a percentage of the zero ethanol isocaloric control rat. The high ethanol group had significantly lower baseline and stimulated PCA and TNF levels than the low ethanol group. For evaluation of the effect of acute exposure to ethanol, Kupffer cells were stimulated with lipopolysaccharide and varying concentrations (0-400 mg/dl) of ethanol. Cells were incubated for 4.5 hr and assayed for PCA and TNF activity. There was dose-dependent inhibition of PCA and TNF, with increasing concentrations of ethanol. These results indicate that whereas exposure to high levels of ethanol depresses Kupffer cell function, lower levels may be immunostimulatory.