Clinically relevant concentrations of ethanol attenuate primed neutrophil bactericidal activity

Adolescent intermittent ethanol (AIE) produces lasting, sex-specific changes in rat body fat independent of changes in white blood cell composition

Early initiation of alcohol use during adolescence, and adolescent binge drinking are risk factors for the development of alcohol use disorder later in life. Adolescence is a time of rapid sex-dependent neural, physiological, and behavioral changes as well as a period of heightened vulnerability to many effects of alcohol. The goal of the present studies was to determine age-related changes in blood (leukocyte populations) and body composition across adolescence and early adulthood, and to investigate whether adolescent intermittent ethanol (AIE) exposure would alter the trajectory of adolescent development on these broad physiological parameters. We observed significant ontogenetic changes in leukocyte populations that were mirrored by an age-related increase in cytokine expression among mixed populations of circulating leukocytes. Despite these developmental changes, AIE did not significantly alter overall leukocyte numbers or cytokine gene expression. However, AIE led to sex-specific changes in body fat mass and fat percentage, with AIE-exposed male rats showing significantly decreased fat levels and female rats showing significantly increased fat levels relative to controls. These changes suggest that while AIE may not alter overall leukocyte levels, more complex phenotypic changes in leukocyte populations could underlie previously reported differences in cytokine expression. Coupled with long-term shifts in adipocyte levels, this could have long-lasting effects on innate immunity and the capacity of individuals to respond to later immunological and physiological threats.

A single alcohol binge impacts on neutrophil function without changes in gut barrier function and gut microbiome composition in healthy volunteers

Alcohol binge drinking is a dangerous drinking habit, associated with neurological problems and inflammation. The impact of a single alcohol binge on innate immunity, gut barrier and gut microbiome was studied. In this cohort study 15 healthy volunteers received 2 ml vodka 40% v/v ethanol/kg body weight. Neutrophil function was studied by flow cytometry; markers of gut permeability and inflammation (lactulose/mannitol/sucrose test, zonulin, calprotectin, diamino-oxidase) were studied with NMR spectroscopy and enzyme-linked immunosorbent assay in urine, stool and serum respectively. Bacterial products in serum were quantified using different reporter cell lines. Gut microbiome composition was studied by 16S rDNA sequencing and bioinformatics analysis. After a single alcohol binge, neutrophils were transiently primed and the response to E.coli stimulation with reactive oxygen species (ROS) production was transiently increased, on the other hand the percentage of neutrophils that did not perform phagocytosis increased. No changes in gut permeability, inflammatory biomarker, bacterial translocation and microbiome composition could be detected up to 4 hours after a single alcohol binge or on the next day. A single alcohol binge in young, healthy volunteers transiently impacts on neutrophil function. Although the exact biological consequence of this finding is not clear yet, we believe that this strengthens the importance to avoid any alcohol binge drinking, even in young, otherwise healthy persons.

Alcohol use disorder increases the risk of necrotizing fasciitis: A nationwide retrospective cohort study

This nationwide retrospective cohort study determined the association between alcohol use disorder (AUD) and the risk of necrotizing fasciitis (NF).This study used health insurance claims data of 52,212 in-patients with AUD and 208,848 controls randomly frequency-matched by age and sex at a 1:4 ratio. The AUD cohort included patients newly diagnosed with AUD between January 1, 2000 and December 31, 2008. The NF event occurrence was observed until December 31, 2011. We used the Kaplan-Meier method to present the cumulative incidence curve and Cox proportional hazard models to depict the risk of NF in patients with AUD.The incidence of NF was 19.4 per 10,000 person-years in the AUD cohort, which was nearly 7.73-fold higher than that in the comparison cohort (2.54 per 10,000 person-years). After adjustment for age, sex, and comorbidities, the patients with AUD exhibited a 3.55-fold higher risk of NF than did the controls (hazard ratio [HR] = 3.55, 95% confidence interval [CI] = 3.00-4.20). Nevertheless, in the AUD groups without any comorbidity, patients with AUD exhibited a significant 15.2-fold higher risk of NF than did the comparison cohort (HR = 15.2, 95% CI = 10.9-21.3). Moreover, the adjusted HRs of NF risk with respect to the severity of AUD were 2.15 (95% CI = 1.76-2.62), 4.54 (95% CI = 3.67-5.62), and 10.7 (95% CI = 8.66-13.2) for mild, moderate, and severe AUD, respectively.This study indicated that AUD should be considered an independent and significant risk factor for NF.

Alcohol, aging, and innate immunity

The global population is aging: in 2010, 8% of the population was older than 65 y, and that is expected to double to 16% by 2050. With advanced age comes a heightened prevalence of chronic diseases. Moreover, elderly humans fair worse after acute diseases, namely infection, leading to higher rates of infection-mediated mortality. Advanced age alters many aspects of both the innate and adaptive immune systems, leading to impaired responses to primary infection and poor development of immunologic memory. An often overlooked, yet increasingly common, behavior in older individuals is alcohol consumption. In fact, it has been estimated that >40% of older adults consume alcohol, and evidence reveals that >10% of this group is drinking more than the recommended limit by the National Institute on Alcohol Abuse and Alcoholism. Alcohol consumption, at any level, alters host immune responses, including changes in the number, phenotype, and function of innate and adaptive immune cells. Thus, understanding the effect of alcohol ingestion on the immune system of older individuals, who are already less capable of combating infection, merits further study. However, there is currently almost nothing known about how drinking alters innate immunity in older subjects, despite innate immune cells being critical for host defense, resolution of inflammation, and maintenance of immune homeostasis. Here, we review the effects of aging and alcohol consumption on innate immune cells independently and highlight the few studies that have examined the effects of alcohol ingestion in aged individuals.

Presence of an Alcohol Use Disorder is Associated with Greater Pneumonia Severity in Hospitalized HIV-Infected Patients

PURPOSE

Pneumonia is common and more severe in human immunodeficiency virus (HIV)-infected patients. Alcohol consumption in pneumonia patients without HIV is associated with excess mortality and morbidity. However, studies are lacking on the impact of alcohol on pneumonia and HIV. Our goal was to determine if alcohol use was an independent risk factor for pneumonia severity in HIV-infected patients.

METHODS

Secondary analysis of prospective cohort study data evaluating early bronchoscopy for pneumonia diagnosis in HIV patients between 2007 and 2011 was conducted. We defined AUDs using an alcohol use disorder identification test (AUDIT) score as follows: ≥8 indicates hazardous drinking and ≥14 indicates dependence. We quantified pneumonia severity using the pneumonia severity index (PSI). Multivariable linear regression was used to investigate the independent association between alcohol and pneumonia severity.

RESULTS

A total of 196 HIV+ individuals comprised our cohort. Most cohort subjects were middle-aged African American men. Most subjects (70 %) reported not taking antiretroviral therapy. The overall prevalence of hazardous drinking was 24 % in our cohort (48/196) with 10 % (19/196) meeting the criteria for alcohol dependence. Alcohol consumption was significantly associated with pneumonia severity (r = 0.25, p < 0.001). Hazardous drinking (β-coefficient 10.12, 95 % CI 2.95-17.29, p = 0.006) and alcohol dependence (β-coefficient 12.89, 95 % CI 2.59-23.18, p = 0.014) were independent risk factors for pneumonia severity. Reported homelessness and men who have sex with men (MSM) status remained independent risk factors for more severe pneumonia after adjustment for the effects of alcohol.

CONCLUSIONS

In a cohort of HIV patients with pneumonia, presence of an AUD was an independent risk factor for pneumonia severity. Homelessness and MSM status were associated with greater pneumonia severity in AUD patients.

Ethanol induces cell cycle arrest and triggers apoptosis via Sp1-dependent p75NTR expression in human neuroblastoma cells

Ethanol exposure has deleterious effects on the central nervous system. Although several mechanisms for ethanol-induced damage have been suggested, the precise mechanism underlying ethanol-induced neuronal cell death remains unclear. Recent studies indicate that the p75 neurotrophin receptor (p75NTR) has a critical role in the regulation of neuronal survival. This study was designed to examine the role of p75NTR in ethanol-induced apoptotic signaling in neuroblastoma cells. Ethanol caused highly increased level of p75NTR expression. The use of small interfering RNA to inhibit p75NTR expression markedly attenuated ethanol-induced cell cycle arrest and apoptosis. DNA binding activity of Sp1 was increased by ethanol, whereas inhibition of Sp1 activity by mithramycin, a Sp1 inhibitor, or short hairpin RNA suppressed ethanol-induced p75NTR expression. In addition, inhibitors of casein kinase 2 (CK2) and extracellular signal-regulated kinase (ERK) augmented ethanol-induced p75NTR expression. Our results also demonstrate that inhibition of ERK and CK2 caused a further increase in the activation of the p75NTR proximal promoter induced by ethanol. This increased activation was partially suppressed by the deletion of the Sp1 binding sites. These results suggest that Sp1-mediated p75NTR expression is regulated at least in part by ERK and CK2 pathways. The present study also showed that treatment with ethanol resulted in significant increases in the expression of p21, but not the levels of p53 and p53 target genes such as Bax, Puma, and Bcl-2. Furthermore, the inhibition of p75NTR expression or Sp1 activity suppressed ethanol-induced p21 expression, cell cycle arrest, and apoptosis. These data suggest that ethanol increases p75NTR expression, and CK2 and ERK signaling inversely regulate Sp1-mediated p75NTR expression in ethanol-treated neuroblastoma cells. Thus, our study provides more insight into the mechanisms underlying ethanol actions.

In vivo hypoxia and a fungal alcohol dehydrogenase influence the pathogenesis of invasive pulmonary aspergillosis

Currently, our knowledge of how pathogenic fungi grow in mammalian host environments is limited. Using a chemotherapeutic murine model of invasive pulmonary aspergillosis (IPA) and (1)H-NMR metabolomics, we detected ethanol in the lungs of mice infected with Aspergillus fumigatus. This result suggests that A. fumigatus is exposed to oxygen depleted microenvironments during infection. To test this hypothesis, we utilized a chemical hypoxia detection agent, pimonidazole hydrochloride, in three immunologically distinct murine models of IPA (chemotherapeutic, X-CGD, and corticosteroid). In all three IPA murine models, hypoxia was observed during the course of infection. We next tested the hypothesis that production of ethanol in vivo by the fungus is involved in hypoxia adaptation and fungal pathogenesis. Ethanol deficient A. fumigatus strains showed no growth defects in hypoxia and were able to cause wild type levels of mortality in all 3 murine models. However, lung immunohistopathology and flow cytometry analyses revealed an increase in the inflammatory response in mice infected with an alcohol dehydrogenase null mutant strain that corresponded with a reduction in fungal burden. Consequently, in this study we present the first in vivo observations that hypoxic microenvironments occur during a pulmonary invasive fungal infection and observe that a fungal alcohol dehydrogenase influences fungal pathogenesis in the lung. Thus, environmental conditions encountered by invading pathogenic fungi may result in substantial fungal metabolism changes that influence subsequent host immune responses.

Mechanisms of neutrophil accumulation in the lungs against bacteria

Bacterial lung diseases are a major cause of morbidity and mortality both in immunocompromised and in immunocompetent individuals. Neutrophil accumulation, a pathological hallmark of bacterial diseases, is critical to host defense, but may also cause acute lung injury/acute respiratory distress syndrome. Toll-like receptors, nucleotide-binding oligomerization domain (NOD)-like receptors, transcription factors, cytokines, and chemokines play essential roles in neutrophil sequestration in the lungs. This review highlights our current understanding of the role of these molecules in the lungs during bacterial infection and their therapeutic potential. We also discuss emerging data on cholesterol and ethanol as environmentally modifiable factors that may impact neutrophil-mediated pulmonary innate host defense. Understanding the precise molecular mechanisms leading to neutrophil influx in the lungs during bacterial infection is critical for the development of more effective therapeutic and prophylactic strategies to control the excessive host response to infection.

Pathoanatomy and clinical correlates of the immunoinflammatory response following orthopaedic trauma

The natural inflammatory response to major trauma may be associated with the development of a systemic inflammatory state, remote multiorgan failure, and death. Although a controlled inflammatory response is beneficial, an exaggerated response can cause serious adverse systemic effects. Early identification of high-risk patients, based on inflammatory markers and genomic predisposition, should help direct intervention in terms of surgical stabilization and biologic response modification. Currently, two markers of immune reactivity, interleukin-6 and human leukocyte antigen-DR class II molecules, appear to have the most potential for regular use in predicting the clinical course and outcome in trauma patients; however, the ability to measure markers of inflammation is still limited at many hospitals. With improving technology and increasing research interest, understanding of the significance of the immunoinflammatory response system in injured patients will continue to evolve.

A recent perspective on alcohol, immunity, and host defense

BACKGROUND

Multiple line of clinical and experimental evidence demonstrates that both acute, moderate, and chronic, excessive alcohol use result in various abnormalities in the functions of the immune system.

METHODS

Medline and PubMed databases were used to identify published reports with particular interest in the period of 2000-2008 in the subject of alcohol use, infection, inflammation, innate, and adaptive immunity.

RESULTS

This review article summarizes recent findings relevant to acute or chronic alcohol use-induced immunomodulation and its consequences on host defense against microbial pathogens and tissue injury. Studies with in vivo and in vitro alcohol administration are both discussed. The effects of alcohol on lung infections, trauma and burn injury, liver, pancreas, and cardiovascular diseases are evaluated with respect to the role of immune cells. Specific changes in innate immune response and abnormalities in adaptive immunity caused by alcohol intake are detailed.

CONCLUSION

Altered inflammatory cell and adaptive immune responses after alcohol consumption result in increased incidence and poor outcome of infections and other organ-specific immune-mediated effects.

Effects of ethanol on pulmonary inflammation in postburn intratracheal infection

Infectious complications are a major cause of mortality in trauma patients. Burn patients with prior ethanol exposure have a worse prognosis than those who sustain injury but had not been drinking. We examined pulmonary infection and lung pathology in mice given ethanol (1.2 g/kg) 30 minutes before being subjected to 13 to 15% total body surface area scald burn followed by intratracheal inoculation with Pseudomonas aeruginosa (1-2 x 10(3) colony-forming units [CFUs]). Survival was monitored for up to 48 hours. Sham control groups had 100% survival after intratracheal infection regardless of ethanol exposure. Infected burned animals had 55% survival; however, survival of infected mice exposed to ethanol and burn injury was significantly lower (27%, P < .0001). When pulmonary infection was evaluated, the lungs of sham groups were negative for bacterial colonies. In addition, at 24 hours there were no significant differences in lung CFUs from infected burned animals regardless of ethanol exposure (3.0 x 10(4)). However, pulmonary bacterial content significantly decreased (1.2 x 10, P < .02) at 48 hours in mice given burn injury alone, where CFUs from the lungs of mice exposed to ethanol prior to burn did not decline (5.4 x 10(5)). At the same time point, lungs from animals given ethanol and burn injury had about a 2-fold (P < .02) increase in leukocyte infiltration and vascular congestion, as well as decreased pulmonary oxygen saturation (82.8%, P < .02), when compared with other treatment groups. In summary, ethanol exposure in postburn intratracheal infection results in the inability to clear pulmonary infection marked by a prolonged pulmonary leukocyte accumulation and a decrease in pulmonary function.

RETRACTED: Effects of ethanol on monosodium urate crystal-induced inflammation

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Image duplication has been observed within Figure 3. The corresponding author has been asked to provide an acceptable explanation for this duplication but has not been able to do so, neither have the original source files been supplied.

Modulating role of alcohol and acetaldehyde on neutrophil and monocyte functions in vitro

Moderate alcohol intake lowers coronary heart disease risk. Because polymorphonuclear neutrophils (PMN) and monocytes (Mo) play a role in atherosclerotic plaque destabilization we investigated in vitro effects of clinically relevant concentrations of ethanol (0.05, 0.125, 0.25, and 0.5%) and its metabolite acetaldehyde (0.0625, 0.125, and 0.5 mM) on human PMN and Mo phagocytic functions. PMN and Mo from healthy volunteers were separated and purified according standard methods and the following parameters were determined: phagocytic activity (percent of phagocytes with at least one ingested particle), ingestion index (number of ingested particles per 100 phagocytic cells), and intracellular killing (percent of dead ingested particles per 100 phagocytes) using acridine orange method and living yeast cells as targets. Reactive oxygen species (ROS) formation of ethanol-treated PMN and Mo was evaluated using 2,7-dichlorofluorescin method and results were expressed as percent of fluorescence-positive cells. Ethanol and acetaldehyde significantly reduced PMN phagocytic functions, with the exception of phagocytic activity, starting at 0.125% for ethanol and 0.0625 mM for acetaldehyde. Mo ingestion and microbicidity were decreased at ethanol concentrations of 0.5% without effect on Mo phagocytic activity. Acetaldehyde impaired Mo ingestion ability starting at 0.0625 mM and phagocytic activity at 0.5 mM while was without effect on Mo microbicidity. ROS production was significantly increased at ethanol concentrations 0.25 and 0.5% in PMN and at 0.5% in Mo. These results might partly explain the beneficial role of moderate use of alcohol on cardiovascular disease.

The effects of ethanol on beta2-integrin and l-selectin on the surface of leukocytes in human whole blood

BACKGROUND

Acute alcohol intoxication is associated with increased susceptibility to infection. In host defense, the expression of adhesion molecules such as beta2-integrin and l-selectin on leukocytes is involved in leukocyte migration to inflamed organ tissue. To elucidate the mechanisms underlying the immunosuppressive effects of ethanol, we investigated whether ethanol pretreatment may influence the changes in adhesion molecule expression induced by lipopolysaccharide (LPS) or interleukin (IL)-8 in human whole blood.

METHODS

Ethanol was added to samples of human whole blood (final concentration: 0%, 0.2%, 0.4%, and 0.8%). Samples were assigned to an unstimulated group and an LPS-stimulated group. In another set of experiments, stimulation was induced by IL-8. After fluorescence labeling of alphaM-subunit of beta2-integrin (CD11b) and l-selectin (CD62L), the expression of CD11b and CD62L were measured using flow cytometry.

RESULTS

Stimulation with LPS significantly upregulated CD11b expression (5.9 +/- 0.9 to 16.3 +/- 1.8, p < 0.05). Ethanol inhibited this LPS-induced upregulation of CD11b (p < 0.001). Stimulation with IL-8 significantly upregulated CD11b expression (5.3 +/- 1.7 to 7.5 +/- 2.7, p < 0.01) and this IL-8-induced upregulation of CD11b was also inhibited by ethanol pretreatment (p < 0.001). In contrast, ethanol did not modify CD62L expression in either unstimulated or stimulated groups.

CONCLUSION

The impairment of CD11b expression on leukocytes suggests that alcohol intake interferes with the migration of leukocytes to sites of inflammation, which may explain, in part, why alcohol intoxication increases susceptibility to infection.

Effects of acute ethanol exposure on the early inflammatory response after excisional injury

BACKGROUND

Alcohol consumption is involved in over half of all trauma-related injuries. These patients are known to exhibit a higher incidence of mortality and morbidity following injury compared with patients not exposed to ethanol. As studies from our laboratory demonstrated that ethanol exposure impairs re-epithelialization and angiogenesis after dermal wounding and because the earlier inflammatory phase of wound healing is likely to influence later responses, we chose to examine neutrophil infiltration and chemokine and proinflammatory cytokine levels in the skin following administration of a dermal excisional wound.

METHODS

BALB/c mice were given ethanol at a dose designed to increase blood alcohol concentration to 100 to 120 mg/dL at 30 minutes after treatment. Mice were then subjected to a full-thickness excisional wound. Wounds from ethanol and saline-treated mice were collected within the first 24 hours postinjury to assess neutrophil infiltration and myeloperoxidase (MPO) activity, neutrophil chemoattractant macrophage inflammatory protein-2 (MIP-2) and KC levels, and proinflammatory cytokine interleukin-1 beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha) levels.

RESULTS

At 12 and 24 hours after injury, MPO in wounds from ethanol-exposed mice was significantly reduced compared with wounds from vehicle-treated animals. Despite this, histological examination of wounds did not reveal a difference in neutrophil infiltration between the 2 groups. Peak levels of MIP-2 and KC observed at 12 hours postinjury were decreased in wounds from ethanol-treated mice by 32 and 45%, respectively, relative to wounds from control mice. Levels of TNFalpha and IL-1beta (potent inducers of MIP-2 and KC, as well as neutrophil activation) were also assessed. Levels of TNFalpha were not elevated in either group after injury. However, IL-1beta demonstrated significantly lower peak levels at 6 hours postinjury in wounds from ethanol-treated mice, 58% less than wounds from controls.

CONCLUSION

These studies reveal that early dermal inflammatory responses including MPO activity, production of MIP-2, KC, and IL-1beta are impaired in mice given ethanol before injury, which may also have detrimental affects on later stages of wound healing.

Alcohol abuse enhances neuroinflammation and impairs immune responses in an animal model of human immunodeficiency virus-1 encephalitis

Neuroinflammatory disorders (including human immunodeficiency virus-1 encephalitis, HIVE) are associated with oxidative stress and inflammatory brain injury, and excessive alcohol use can exacerbate tissue damage. Using a murine model of HIVE, we investigated the effects of alcohol abuse on the clearance of virus-infected macrophages and neuroinflammation. Severe combined immunodeficient mice were reconstituted with human lymphocytes, and encephalitis was induced by intracranial injection of HIV-1-infected monocyte-derived macrophages (HIV-1(+) MDM). Animals were fed an ethanol-containing diet beginning 2 weeks before lymphocyte engraftment and for the entire duration of the experiment. Lymphocyte engraftment was not altered by ethanol exposure. Alcohol-mediated immunosuppression in ethanol-fed mice was manifested by a significant decrease in CD8(+)/interferon-gamma(+) T lymphocytes, a fivefold increase in viremia, and diminished expression of immunoproteasomes in the spleen. Although both groups showed similar amounts of CD8(+) T-lymphocyte infiltration in brain areas containing HIV-1(+) MDMs, ethanol-fed mice featured double the amounts of HIV-1(+) MDMs in the brain compared to controls. Ethanol-exposed mice demonstrated higher microglial reaction and enhanced oxidative stress. Alcohol exposure impaired immune responses (increased viremia, decreased immunoproteasome levels, and prevented efficient elimination of HIV-1(+) MDMs) and enhanced neuroinflammation in HIVE mice. Thus, alcohol abuse could be a co-factor in progression of HIV-1 infection of the brain.

Alcohol and trauma: the perfect storm

Alcohol misuse, when combined with the right circumstances, culminates in a "Perfect Storm" that has catastrophic results. Alcohol misuse impairs judgment and increases the likelihood of serious injury. Once injured, the intoxicated patient is more likely to be hypotensive and less likely to be able to protect his or her airway. Alcohol also impairs multiple compensatory responses to injury that are critical to survival, thereby increasing the likelihood of serious complications. When complications do occur, they may be more severe for intoxicated patients because both acute and chronic ethanol use adversely affect immunity. Thus, all phases of trauma care are potentially affected by excessive alcohol use. This paper presents facts about trauma care and the physiologic consequences and clinical implications of alcohol intoxication. Further, it shows how health-care costs increase when evaluating and managing an intoxicated trauma patient. This financial burden further escalates in the surgical ICU because the care of an intoxicated patient falls outside the realm of standard care. Trauma surgeons, perhaps more than other health-care providers, have a unique opportunity and a responsibility to address potential alcohol misuse with their patients. They witness the Perfect Storm almost daily and are fully aware of the short- and long-term consequences of alcohol misuse. A trauma center visit provides an opportune time and place to incorporate alcohol screening and brief interventions as a part of standard trauma care.

Lindane stimulates neutrophils by selectively activating phospholipase C and phosphoinositide-kinase activity

The organochlorine insecticide lindane is a known activator of neutrophil responses. In this work we delineated the biochemical pathways by which lindane stimulates neutrophil oxidant production. Plasma membrane GTPase activity was not stimulated by lindane, ruling out a role for lindane-induced activation of G-proteins or G-protein coupled receptors, whereas inhibition of phospholipase C inhibited lindane-induced oxidant production. Together these data pointed to phospholipase C as the direct target of lindane activation. Type I phosphoinositide 3-kinase was not significantly activated by lindane and an inhibitor of phosphoinositide 3-kinases inhibited oxidant production by only 40%. Thus, Type I phosphoinositide 3-kinase played a minor role, if any, in lindane-induced oxidant production. Lindane stimulated an increase in phosphatidylinositol phosphate suggesting a Type II or III phosphotidylinositol 3-kinase or phosphatidylinositol 4-kinase activity was also stimulated.

Ethanol blocks leukocyte recruitment and endothelial cell activation in vivo and in vitro

Immune system impairment and increased susceptibility to infection among alcohol abusers is a significant but not well-understood problem. We hypothesized that acute ethanol administration would inhibit leukocyte recruitment and endothelial cell activation during inflammation and infection. Using LPS and carrageenan air pouch models in mice, we found that physiological concentrations of ethanol (1-5 g/kg) significantly blocked leukocyte recruitment (50-90%). Because endothelial cell activation and immune cell-endothelial cell interactions are critical regulators of leukocyte recruitment, we analyzed the effect of acute ethanol exposure on endothelial cell activation in vivo using the localized Shwartzman reaction model. In this model, ethanol markedly suppressed leukocyte accumulation and endothelial cell adhesion molecule expression in a dose-dependent manner. Finally, we examined the direct effects of ethanol on endothelial cell activation and leukocyte-endothelial cell interactions in vitro. Ethanol, at concentrations within the range found in human blood after acute exposure and below the levels that induce cytotoxicity (0.1-0.5%), did not induce endothelial cell activation, but significantly inhibited TNF-mediated endothelial cell activation, as measured by adhesion molecule (E-selectin, ICAM-1, VCAM-1) expression and chemokine (IL-8, MCP-1, RANTES) production and leukocyte adhesion in vitro. Studies exploring the potential mechanism by which ethanol suppresses endothelial cell activation revealed that ethanol blocked NF-kappaB nuclear entry in an IkappaBalpha-dependent manner. These findings support the hypothesis that acute ethanol overexposure may increase the risk of infection and inhibit the host inflammatory response, in part, by blocking endothelial cell activation and subsequent immune cell-endothelial cell interactions required for efficient immune cell recruitment.

Deficient phospholipase C activity in blood polimorphonuclear neutrophils from patients with liver cirrhosis

BACKGROUND/AIMS

Circulating neutrophils from cirrhotic patients have a reduced capacity to generate superoxide anion (O(2)(-)), which might contribute to frequent bacterial infections in these patients. We studied the signal transduction pathways involved in the generation of O(2)(-) in neutrophils from 98 cirrhotic patients and 46 healthy controls.

METHODS

We measured O(2)(-) production in neutrophils induced by fMLP, opsonized zymosan, TNF alpha, NaF, AlF(4)(-), A23187 and phorbol myristate acetate. Furthermore, we measured phospholipase C activity in neutrophils from healthy controls and end-stage cirrhotic patients.

RESULTS

O(2)(-) production was decreased in neutrophils from patients in response to fMLP, opsonized zymosan and TNF alpha. Likewise, response of these cells to G-protein stimulation by fluorides was also decreased. These reduced responses correlated significantly with the degree of liver dysfunction. On the contrary, neutrophils from patients responded normally to A23187 and phorbol esters stimulation indicating that Ca(2+)- and PKC-dependent pathways are intact in these cells. Finally, phospholipase C activity was markedly reduced in neutrophils from end-stage liver cirrhosis.

CONCLUSIONS

These data confirm that O(2)(-) generation by neutrophils is decreased in patients with cirrhosis, particularly in those with more severe liver dysfunction, and suggest that this defect involves phosphatidylinositol specific phospholipase C activity.

Ethanol abuse and the trauma patient

BACKGROUND

Alcohol intoxication has long been associated with an increased risk of injury from a number of mechanisms and with trauma recidivism. It is less certain whether alcohol abuse is associated with worse outcomes for a given degree of injury.

METHODS

Review of the pertinent English-language literature.

RESULTS

The vasodilator effects of alcohol may hamper fluid resuscitation, especially in head-injured patients. Acute and chronic alcohol intoxication both have substantial effects on the cellular and molecular responses necessary to fight infection. High alcohol concentrations exert an immunosuppressive effect on production of proinflammatory cytokines such as tumor necrosis factor and interleukin-1. However, the clinical effects of the immunosuppression are variable and difficult to discern in heterogeneous trauma patient populations with variable degrees of intoxication.

CONCLUSION

Alcohol has a profound impact on the epidemiology of injury, but the physiology and biochemical effects in an individual patient may be difficult to predict. Identification of intoxicated persons is essential, despite economic disincentives to do so, because even brief targeted intervention programs can decrease substantially the patient's risk of subsequent injury.

Alcohol, injury, and cellular immunity

It is widely accepted that alcohol exposure is a causative factor in the occurrence of burn or other traumatic injury. It is less well known that individuals who have consumed alcohol before sustaining an injury suffer from increased morbidity and mortality compared with the morbidity and mortality of non-alcohol-consuming subjects with similar injuries. Complications due to bacterial infection are the most common burn sequelae in injured patients and are frequently associated with depressed immunity. Independently, alcohol exposure and injury have been shown to influence cellular immunity negatively. These changes in immunity are closely linked to injury- or alcohol-induced alterations in the cytokine milieu in both clinical studies and animal models. Not surprisingly, the combination of insult of alcohol exposure and burn injury results in immune suppression that is greater in magnitude and duration compared with either insult alone. The combined effects of alcohol and injury on immunity have been examined in a limited number of studies. However, results of these studies support the suggestion that altered cytokine production is an integral part of the immune dysregulation and increased mortality that is observed. In particular, the increased presence of macrophage-derived mediators observed after burn or alcohol exposure alone seems to be synergistically increased in a combined injury model. Although more research is needed, it is likely that therapeutic modalities that include manipulation of cytokine networks to boost cellular immunity may improve outcome for patients who sustain injuries subsequent to consuming alcohol.

Acquired disorders of phagocyte function complicating medical and surgical illnesses

There is evidence that acquired dysfunction of neutrophils, monocytes, or macrophages is an important cause of infection in patients with diabetes mellitus, renal or hepatic failure, alcoholism, autoimmune diseases, influenza or human immunodeficiency virus infection, burns, and trauma. Distinguishable mechanisms of acquired phagocyte dysfunction include inhibitory effects of metabolic disturbances (e.g., hyperglycemia, uremia), chemical toxins (e.g., ethanol), viral proteins on phagocyte activation, and pathologic activation of phagocytes in the circulation (e.g., after hemodialysis, burns, or cardiopulmonary bypass). Although the burden of morbidity and mortality resulting from acquired phagocyte dysfunction appears to be vast, research in this area has been hampered by the complexity of the underlying illnesses and by limitations of laboratory assays and clinical study methodology. Given the advent of improved assays of phagocyte functions and treatments that can enhance these functions, there is a pressing need for more prospective studies of acquired phagocyte dysfunction.

Phosphatidic acid regulates tyrosine phosphorylating activity in human neutrophils: enhancement of Fgr activity

In human neutrophils, the activation of phospholipase D and the Tyr phosphorylation of proteins are early signaling events upon cell stimulation. We found that the pretreatment of neutrophils with ethanol (0.8%) or 1-butanol (0.3%), which results in the accumulation of phosphatidylalcohol at the expense of phosphatidic acid (PA), decreased the phorbol myristate acetate-stimulated Tyr phosphorylation of endogenous proteins (42, 115 kDa). When neutrophil cytosol was incubated in the presence or absence of PA, these and other endogenous proteins became Tyr-phosphorylated in a PA-dependent manner. In contrast, phosphatidylalcohols exhibited only 25% (phosphatidylethanol) or 5% (phosphatidylbutanol) of the ability of PA to stimulate Tyr phosphorylation in the cell-free assay. Similarly, other phospholipids (phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine, phosphatidylinositol, polyphosphoinositides, and sphingosine 1-phosphate) showed little ability to stimulate Tyr phosphorylation. These data suggest that PA can function as an intracellular regulator of Tyr phosphorylating activity. Gel filtration chromatography of leukocyte cytosol revealed a peak of PA-dependent Tyr phosphorylating activity distinct from a previously described PA-dependent phosphorylating activity (Waite, K. A., Wallin, R., Qualliotine-Mann, D., and McPhail, L. C. (1997) J. Biol. Chem. 272, 15569-15578). Among the protein Tyr kinases expressed in neutrophils, only Fgr eluted exclusively in the peak of PA-dependent Tyr phosphorylating activity. Importantly, Fgr isolated from unstimulated neutrophil lysates showed increased activity in the presence of PA but not phosphatidylbutanol. Moreover, the pretreatment of neutrophils with 1-butanol decreased Fgr activity in cells stimulated with formyl-methionyl-leucyl phenylalanine plus dihydrocytochalasin B. Together, these results suggest a new second messenger role for PA in the regulation of Tyr phosphorylation.

Detection of acute alcohol intoxication and chronic alcohol dependence by trauma center staff

BACKGROUND

Trauma patients with acute alcohol intoxication or chronic alcohol dependence are at greater risk for morbidity and mortality. We hypothesized that relying on clinical suspicion to detect acute alcohol intoxication and chronic alcohol dependence in trauma patients is inaccurate, influenced by injury factors, and biased by race, gender, age, and socioeconomic status.

METHODS

Trauma patients were screened with a blood alcohol concentration and with the Short Michigan Alcohol Screening Test and CAGE questionnaire. Before screening, physicians and emergency department nurses were asked whether the patient was acutely intoxicated (blood alcohol concentration > 100 mg/ dL) or had a chronic alcohol problem. Sensitivity, specificity, positive, and negative predictive values were determined by comparing responses with blood alcohol concentration, Short Michigan Alcohol Screening Test, and CAGE questionnaire results, stratified by injury and demographic factors.

RESULTS

Clinical evaluations were obtained on 462 patients. Overall, 23% of acutely intoxicated patients were not identified by physicians. The miss rate increased to one third in severely injured, chemically paralyzed, or intubated patients. Specificity was also poor. Patients with a negative blood alcohol concentration were more likely to be falsely suspected of intoxication if they were either young, male, perceived as disheveled, uninsured, or having a low income (p < 0.05). Staff identified < 50% of patients with a positive Short Michigan Alcohol Screening Test or CAGE, and falsely identified 26% of patients as alcoholic.

CONCLUSIONS

Formal alcohol screening should be routine because clinical detection of acute alcohol intoxication and dependence is inaccurate. Screening should also be routine to avoid discriminatory bias attributable to patient characteristics.