Acute Ethanol Intoxication Inhibits Neutrophil beta2-Integrin Expression in Rats During Endotoxemia

Impact of Alcohol on Inflammation, Immunity, Infections, and Extracellular Vesicles in Pathogenesis

Alcohol consumption is a widespread social activity with a complex and multifaceted impact on human health. Although moderate alcohol consumption has been associated with certain potential health benefits, excessive or chronic alcohol use can disrupt the body's immune balance, promote inflammation, and increase susceptibility to infections. The deleterious effects associated with alcohol toxicity include the loss of cell integrity. When cells lose their integrity, they also lose the capacity to communicate with other systems. One of the systems disturbed by alcohol toxicity is extracellular vesicle (EV)-mediated communication. EVs are critical mediators of cell-to-cell communication. They play a significant role in alcohol-induced pathogenesis, facilitating communication and molecular exchange between cells, thereby potentially contributing to alcohol-related health issues. Investigating their involvement in this context is fundamental to resolving the intricate mechanisms behind the health consequences of alcohol use and may pave the way for innovative approaches for mitigating the adverse effects of alcohol on immune health. Understanding the role of EVs in the context of alcohol-induced pathogenesis is essential for comprehending the mechanisms behind alcohol-related health issues.

The inflammatory spectrum of cardiomyopathies

Infiltration of the myocardium with various cell types, cytokines and chemokines plays a crucial role in the pathogenesis of cardiomyopathies including inflammatory cardiomyopathies and myocarditis. A more comprehensive understanding of the precise immune mechanisms involved in acute and chronic myocarditis is essential to develop novel therapeutic approaches. This review offers a comprehensive overview of the current knowledge of the immune landscape in cardiomyopathies based on etiology. It identifies gaps in our knowledge about cardiac inflammation and emphasizes the need for new translational approaches to improve our understanding thus enabling development of novel early detection methods and more effective treatments.

Ethanol Intoxication Impairs Respiratory Function and Bacterial Clearance and Is Associated With Neutrophil Accumulation in the Lung After Streptococcus pneumoniae Infection

Alcohol consumption is commonplace in the United States and its prevalence has increased in recent years. Excessive alcohol use is linked to an increased risk of infections including pneumococcal pneumonia, mostly commonly caused by Streptococcus pneumoniae. In addition, pneumonia patients with prior alcohol use often require more intensive treatment and longer hospital stays due to complications of infection. The initial respiratory tract immune response to S. pneumoniae includes the production of pro-inflammatory cytokines and chemokines by resident cells in the upper and lower airways which activate and recruit leukocytes to the site of infection. However, this inflammation must be tightly regulated to avoid accumulation of toxic by-products and subsequent tissue damage. A majority of previous work on alcohol and pneumonia involve animal models utilizing high concentrations of ethanol or chronic exposure and offer conflicting results about how ethanol alters immunity to pathogens. Further, animal models often employ a high bacterial inoculum which may overwhelm the immune system and obscure results, limiting their applicability to the course of human infection. Here, we sought to determine how a more moderate ethanol exposure paradigm affects respiratory function and innate immunity in mice after intranasal infection with 10⁴ colony forming units of S. pneumoniae. Ethanol-exposed mice displayed respiratory dysfunction and impaired bacterial clearance after infection compared to their vehicle-exposed counterparts. This altered response was associated with increased gene expression of neutrophil chemokines Cxcl1 and Cxcl2 in whole lung homogenates, elevated concentrations of circulating granulocyte-colony stimulating factor (G-CSF), and higher neutrophil numbers in the lung 24 hours after infection. Taken together, these findings suggest that even a more moderate ethanol consumption pattern can dramatically modulate the innate immune response to S. pneumoniae after only 3 days of ethanol exposure and provide insight into possible mechanisms related to the compromised respiratory immunity seen in alcohol consumers with pneumonia.

Liver-lung axes in alcohol-related liver disease

Alcohol-related liver disease (ALD) and alcohol-related susceptibility to acute lung injury are the leading causes of morbidity and mortality due to chronic alcohol abuse. Most commonly, alcohol-induced injury to both organs are evaluated independently, although they share many parallel mechanisms of injury. Moreover, recent studies indicate that there is a potential liver lung axis that may contribute to organ pathology. This mini-review explores established and potential mechanisms of organ-organ crosstalk in ALD and alcohol-related lung injury.

Innate Immunity and Alcohol

The innate immunity has evolved during millions of years, and thus, equivalent or comparable components are found in most vertebrates, invertebrates, and even plants. It constitutes the first line of defense against molecules, which are either pathogen-derived or a danger signal themselves, and not seldom both. These molecular patterns are comprised of highly conserved structures, a common trait in innate immunity, and constitute very potent triggers for inflammation mediated via extracellular or intracellular pattern recognition receptors. Human culture is often interweaved with the consumption of alcohol, in both drinking habits, its acute or chronical misuse. Apart from behavioral effects as often observed in intoxicated individuals, alcohol consumption also leads to immunological modulation on the humoral and cellular levels. In the last 20 years, major advances in this field of research have been made in clinical studies, as well as in vitro and in vivo research. As every physician will experience intoxicated patients, it is important to be aware of the changes that this cohort undergoes. This review will provide a summary of the current knowledge on the influence of alcohol consumption on certain factors of innate immunity after a hit, followed by the current studies that display the effect of alcohol with a description of the model, the mode of alcohol administration, as well as its dose. This will provide a way for the reader to evaluate the findings presented.

Alcohol Decreases Organic Dust-Stimulated Airway Epithelial TNF-Alpha Through a Nitric Oxide and Protein Kinase-Mediated Inhibition of TACE

BACKGROUND

Farm workers in rural areas consume more alcohol than those who reside in urban areas. Occupational exposures such as agricultural work can pose hazards on the respiratory system. It is established that hog barn dust induces inflammation in the airway, including the release of cytokines such as tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and IL-8. We have shown that alcohol alters airway epithelial innate defense through changes in both nitric oxide (NO) and cAMP-dependent protein kinase A (PKA). Simultaneous exposure to hog barn dust and alcohol decreases inflammatory mediators, TNF-α, IL-6, and IL-8, in mice. Previously, mice exposed to both alcohol and hog barn dust showed a depleted amount of lymphocytes compared to mice exposed only to hog barn dust. Weakening of the innate immune response could lead to enhanced susceptibility to disease. In addition, mice that were co-exposed to hog barn dust and alcohol also experienced increased mortality.

METHODS

Because we recently demonstrated that PKA activation inhibits the TNF-α sheddase, TNF-α-converting enzyme (TACE), we hypothesized that an alcohol-mediated PKA pathway blocks TACE activity and prevents the normative inflammatory response to hog barn dust exposure. To delineate these effects, we used PKA pathway inhibitors (adenylyl cyclase [AC], cAMP, and PKA) to modulate the effects of alcohol on dust-stimulated TNF-α release in the bronchial epithelial cell line, BEAS-2B. Alcohol pretreatment blocked TACE activity and TNF-α release in hog barn dust-treated cells.

RESULTS

Alcohol continued to block hog barn dust-mediated TNF-α release in the presence of the particulate AC inhibitor, SQ22,536. The soluble adenylyl cyclase inhibitor, KH7, however, significantly increased the inflammatory response to hog barn dust. phosphodiesterase 4 inhibitors significantly elevated cAMP and enhanced alcohol-mediated inhibition of dust-stimulated TNF-α release. In addition, the NO synthase inhibitor, l-NMMA, also reversed the alcohol-blocking effect on dust-stimulated TNF-α.

CONCLUSIONS

These data suggest that alcohol requires a soluble cyclase-generated cAMP-PKA pathway that is dependent upon the action of NO to inhibit TACE and TNF-α release. These findings support our observations that alcohol functions through a dual NO and PKA pathway in bronchial epithelial cells.

Potential Role of the Gut/Liver/Lung Axis in Alcohol-Induced Tissue Pathology

Both Alcoholic Liver Disease (ALD) and alcohol-related susceptibility to acute lung injury are estimated to account for the highest morbidity and mortality related to chronic alcohol abuse and, thus, represent a focus of intense investigation. In general, alcohol-induced derangements to both organs are considered to be independent and are often evaluated separately. However, the liver and lung share many general responses to damage, and specific responses to alcohol exposure. For example, both organs possess resident macrophages that play key roles in mediating the immune/inflammatory response. Additionally, alcohol-induced damage to both organs appears to involve oxidative stress that favors tissue injury. Another mechanism that appears to be shared between the organs is that inflammatory injury to both organs is enhanced by alcohol exposure. Lastly, altered extracellular matrix (ECM) deposition appears to be a key step in disease progression in both organs. Indeed, recent studies suggest that early subtle changes in the ECM may predispose the target organ to an inflammatory insult. The purpose of this chapter is to review the parallel mechanisms of liver and lung injury in response to alcohol consumption. This chapter will also explore the potential that these mechanisms are interdependent, as part of a gut-liver-lung axis.

Alcohol abuse and Streptococcus pneumoniae infections: consideration of virulence factors and impaired immune responses

Alcohol is the most frequently abused substance in the world. Both acute and chronic alcohol consumption have diverse and well-documented effects on the human immune system, leading to increased susceptibility to infections like bacterial pneumonia. Streptococcus pneumoniae is the most common bacterial etiology of community-acquired pneumonia worldwide. The frequency and severity of pneumococcal infections in individuals with a history of alcohol abuse is much higher than the general population. Despite this obvious epidemiological relevance, very few experimental studies have focused on the interaction of pneumococci with the immune system of a host acutely or chronically exposed to alcohol. Understanding these host-pathogen interactions is imperative for designing effective prophylactic and therapeutic interventions for such populations. Recent advances in pneumococcal research have greatly improved our understanding of pneumococcal pathogenesis and virulence mechanisms. Additionally, a large body of data is available on the effect of alcohol on the physiology of the lungs and the innate and adaptive immune system of the host. The purpose of this review is to integrate the available knowledge in these diverse areas of for a better understanding of the how the compromised immune system derived from alcohol exposure responds to pneumococcal infections.

Innate immunity of the liver microcirculation

The liver is a complex organ with a unique microcirculation and both synthetic and immune functions. Innate immune responses have been studied in response to single inflammatory mediators and several clinically relevant models of infection and injury. While standard histological techniques have been used in many models, the liver microcirculation is also amenable to in vivo examination using epifluorescent, confocal and transillumination intravital microscopy. These techniques have begun to clarify not only the molecular mechanisms but also the specific cell populations involved in the liver inflammation. In this review, we discuss the cells and mediators involved in hepatic innate immunity in simple and complex models of injury and infection, and present the view that the liver microcirculation utilizes non-classical pathways for leukocyte recruitment.

Alcohol-use disorders in the critically ill patient

Alcohol abuse and dependence, referred to as alcohol-use disorders (AUDs), affect 76.3 million people worldwide and account for 1.8 million deaths per year. AUDs affect 18.3 million Americans (7.3% of the population), and up to 40% of hospitalized patients have AUDs. This review discusses the development and progression of critical illness in patients with AUDs. In contrast to acute intoxication, AUDs have been linked to increased severity of illness in a number of studies. In particular, surgical patients with AUDs experience higher rates of postoperative hemorrhage, cardiac complications, sepsis, and need for repeat surgery. Outcomes from trauma are worse for patients with chronic alcohol abuse, whereas burn patients who are acutely intoxicated may not have worse outcomes. AUDs are linked to not only a higher likelihood of community-acquired pneumonia and sepsis but also a higher severity of illness and higher rates of nosocomial pneumonia and sepsis. The management of sedation in patients with AUDs may be particularly challenging because of the increased need for sedatives and opioids and the difficulty in diagnosing withdrawal syndrome. The health-care provider also must be watchful for the development of dangerous agitation and violence, as these problems are not uncommonly seen in hospital ICUs. Despite studies showing that up to 40% of hospitalized patients have AUDs, relatively few guidelines exist on the specific management of the critically ill patient with AUDs. AUDs are underdiagnosed, and a first step to improving patient outcomes may lie in systematically and accurately identifying AUDs.

Alcohol abuse and pulmonary disease

ARDS is a severe form of lung injury characterized by increased permeability of the alveolar capillary membrane, diffuse alveolar damage, the accumulation of proteinaceous interstitial and intra-alveolar edema, and the presence of hyaline membranes. These pathological changes are accompanied by physiological alterations, including severe hypoxemia, an increase in pulmonary dead space, and decreased pulmonary compliance. Approximately 200,000 individuals develop ARDS in the United States each year, and nearly 50% of these patients have a history of alcohol abuse. We have identified alcohol abuse as an independent risk factor for the development of ARDS, and more recent studies have validated these findings in patients following lung resection and blood transfusion. In ARDS survivors, alcohol abuse is also associated with an increased duration of mechanical ventilation and prolonged ICU length of stay. Despite studies aimed at improving outcomes in patients with ARDS, the mortality remains high at > 40%]. For those who abuse alcohol, the mortality is even higher, at 65%. In this review, we will discuss the relationship between alcohol abuse and ARDS, the effects of alcohol abuse on pulmonary function, and future directions and potential therapeutic targets for patients at risk for ARDS as a result of alcohol abuse, which impairs immune function, decreases pulmonary antioxidant capacity, decreases alveolar epithelial cell function, alters activation of the renin angiotensin system, and impairs GM-CSF signaling. These pathways represent potential therapeutic targets for patients at risk for ARDS as a result of alcohol abuse.

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.

The association between blood alcohol level and infectious complications among burn patients

Approximately 50% of fatal and 15% of nonfatal burn-injured patients have detectable blood alcohol content (BAC) at the time of admission, and it is hypothesized that alcohol exacerbates burn-related immunosuppression. The purpose of this study was to evaluate the association between BAC and infectious complications in burn patients. The study population consisted of 1161 burn patients admitted to a large academic burn center between January 1998 and June 2007. Patients were categorized into no BAC (0.0 g/100 ml), low/moderate BAC (>0.0 and <0.1 g/100 ml) and high BAC (> or =0.1 g/100 ml) groups based on BAC at time of admission. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated for associations between pneumonia, sepsis, urinary tract infection, line infection, and wound infection and BAC, adjusted for total burn surface area and inhalation injury. Relative to no BAC patients, both low/moderate and high BAC patients had nonsignificantly increased risk for most infectious complications. High BAC patients were at significantly increased risk for any infectious complication (RR 2.06, CI 1.25-3.41) and pneumonia (RR 2.06, CI 1.04-4.09) and a nonsignificantly increased risk of urinary tract infection (RR 2.12, CI 0.0.94-4.78). Results suggest that preinjury alcohol consumption places patients at an increased risk for infectious complications, most notably pneumonia. Further studies examining the relationship between alcohol and pneumonia among burn patients will help elucidate the reason for the increased risk observed in the current study and suggest ways to prevent infection for this particular subgroup of burn patients.

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.

Exposure-dependent effects of ethanol on the innate immune system

Extensive evidence indicates that ethanol (alcohol) has immunomodulatory properties. Many of its effects on innate immune response are dose dependent, with acute or moderate use associated with attenuated inflammatory responses, and heavy ethanol consumption linked with augmentation of inflammation. Ethanol may modify innate immunity via functional alterations of the cells of the innate immune system. Mounting evidence indicates that ethanol can diversely affect antigen recognition and intracellular signaling events, which include activation of mitogen activated protein kinases, and NFkappaB, mediated by Toll-like receptors, leading to altered inflammatory responses. The mechanism(s) underlying these changes may involve dose-dependent effects of ethanol on the fluidity of cell membrane, resulting in interference with the timely assembly or disassembly of lipid rafts. Ethanol could also modify cell activation by specific interactions with cell membrane molecules.

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.

Acute alcohol intoxication suppresses the pulmonary ELR-negative CXC chemokine response to lipopolysaccharide

Alcohol abuse impairs the pulmonary immune response to infection and increases the morbidity and mortality of bacterial pneumonia. Acute alcohol intoxication suppresses lung expression of CXC chemokines bearing the Glu-Leu-Arg motif (ELR+) following lipopolysaccharide (LPS) challenge, but its effect on the structurally related ELR- CXC chemokines, which attract T cells, is unknown. We therefore investigated the effect of acute alcohol intoxication on the pulmonary response to intratracheal (i.t.) LPS challenge for the ELR- CXC chemokines monokine induced by gamma (MIG or CXCL9), interferon-inducible protein 10 (IP-10 or CXCL10), and interferon-inducible T cell alpha chemoattractant (I-TAC or CXCL11). Male C57BL/6 or C3H/HeN mice were given an intraperitoneal injection of ethanol (3.0 g/kg) or phosphate buffered saline 30 min before i.t. LPS challenge. Chemokine mRNA transcripts were measured at 0, 2, 6, and 16 h. Acute alcohol intoxication inhibited the lung's expression of all three chemokine genes in response to LPS. Lung IFN-gamma mRNA was also inhibited by acute intoxication over the same time course. The in vitro effect of ethanol on chemokine secretion was further studied in the MH-S alveolar macrophage cell line. IP-10, MIG, and I-TAC in response to LPS were enhanced by exogenous interferon (IFN)-gamma, and these responses were blunted by exposure to ethanol. Alcohol exposure did not affect MH-S cell nuclear factor kappa beta p65 nuclear localization during challenge, despite dose-dependent inhibition of Erk 1/2 phosphorylation. In addition, phospho-signal transduction and activator of transcription 1 was not decreased in the presence of acute ethanol, thereby indicating that acute intoxication does not affect IFN-gamma signaling in MH-S cells. Recruitment of CD3+ T cells into the alveolar space 4 days after LPS challenge was moderately impaired by acute ethanol intoxication. These results implicate acute ethanol intoxication as a significant inhibitor of lymphocyte chemoattractant expression during pulmonary inflammation.

Stable adhesion and migration of human neutrophils requires phospholipase D-mediated activation of the integrin CD11b/CD18

The pathways regulating integrin-mediated adhesion during neutrophil migration are incompletely defined. Using a flow-based model in which human neutrophils rolling on P-selectin were activated to migrate by the chemoattractant peptide fMLP, we investigated the role of phospholipase D (PLD). fMLP-stimulated PLD generation of phosphatidate (PtdOH); while inhibition of PtdOH production with butan-1-ol had no effect on the initial immobilisation of rolling neutrophils (supported by activation of constitutively surface-expressed beta(2)-integrin CD11b/CD18) it impaired longer-term stability of adhesion and reduced the rate of migration (supported by activation of de novo-exocytosed CD11b/CD18). PtdOH regulated these processes by controlling activation of exocytosed CD11b/CD18, and appeared to act by directly stimulating phosphatidylinositol 4-phosphate 5-kinase type I to generate phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)). Cell-permeable PtdIns(4,5)P(2) recovered migration of neutrophils after PLD inhibition; PtdIns(4,5)P(2) appeared to act by promoting talin binding to CD18 and hence activating CD11b/CD18, as migration was inhibited when neutrophils were loaded with peptides previously shown to block the interaction between PtdIns(4,5)P(2) and talin or talin and CD18. Thus, these data indicate that PLD-synthesised PtdOH stimulates the generation of PtdIns(4,5)P(2), which in turn mediates talin binding to, and activation of, CD11b/CD18 required for neutrophil stable adhesion and migration.

Effects of systemic and local CXC chemokine administration on the ethanol-induced suppression of pulmonary neutrophil recruitment

BACKGROUND

Acute alcohol intoxication impairs the neutrophil response to intrapulmonary infection, resulting in impaired host defense and increased patient morbidity and mortality. We recently showed that intratracheal (IT) chemokine administration promotes pulmonary neutrophil migration in rats and that this process is enhanced by systemic administration of the Glu-Leu-Arg (ELR+) and CXC chemokine cytokine-induced neutrophil chemoattractant (CINC). Here we hypothesized that exogenous chemokine administration would mitigate the suppressive effect of alcohol on neutrophil recruitment into the lung.

METHODS

Macrophage inflammatory protein-2 (MIP-2), a rat ELR+ CXC chemokine, or live Klebsiella pneumoniae (K. pneumoniae) was administered it to induce alveolar neutrophil migration in the absence or presence of acute ethanol intoxication. Depending on the experimental protocol, rats received either intravenous (IV) CINC or IT chemokines (CINC and MIP-2) 20 min after it MIP-2 or K. pneumoniae. Rats were euthanized 90 min or four hr after the first IT injection for sample collection.

RESULTS

Neutrophil counts were significantly elevated in bronchoalveolar lavage fluid (BALF) of rats receiving IT MIP-2 compared with vehicle-treated rats, and this response was significantly decreased in animals pretreated with ethanol. CINC IV enhanced the neutrophil response to IT MIP-2 in both the absence and presence of acute ethanol intoxication. In rats challenged with K. pneumoniae, ethanol pretreatment significantly reduced BALF levels of CINC and MIP-2, suppressed alveolar neutrophil recruitment, and decreased whole-lung myeloperoxidase activity. CINC IV did not alter BALF neutrophil counts in the absence or presence of ethanol administration 4 hr after IT K. pneumoniae. Alternatively, IT chemokine instillation partially restored BALF neutrophil recruitment but not whole-lung myeloperoxidase activity in ethanol-treated rats.

CONCLUSIONS

Ethanol significantly inhibits the pulmonary inflammatory responses to both MIP-2 and K. pneumoniae. Exogenous chemokine administration may be a useful means to enhance host defenses in the ethanol-intoxicated host, although the results of this study also indicate that ethanol intoxication can impair neutrophil recruitment, independent of its effects on local chemotactic gradients.

Consequences of alcohol-induced early dysregulation of responses to trauma/hemorrhage

Acute alcohol intoxication is a frequent underlying condition associated with traumatic injury. Studies from our laboratory have been designed to examine the early hemodynamic, proinflammatory, and neuroendocrine alterations in responses to hemorrhagic shock in surgically catheterized, conscious, unrestrained, male Sprague-Dawley rats during acute alcohol intoxication (1.75-g/kg bolus, followed by a constant 15-h infusion at a rate of 250-300 mg/kg/h). With both fixed-pressure (40 mm Hg) and fixed-volume (50%) hemorrhagic shock, followed by fluid resuscitation with Ringer's lactate, acute (15 h) alcohol intoxication has been shown to impair significantly the immediate hemodynamic, metabolic, and inflammatory counterregulatory responses to hemorrhagic shock. Alcohol intoxication enhanced hemodynamic instability during blood loss and impaired the recovery of mean arterial blood pressure during fluid resuscitation. Activation of neuroendocrine pathways involved in restoring hemodynamic stability was significantly attenuated in alcohol-intoxicated hemorrhaged animals. The hemodynamic and neuroendocrine impairment is associated with enhanced expression of lung and spleen tumor necrosis factor, and it suppressed circulating neutrophil function. In addition, neuroimmune regulation of cytokine production by spleen-derived macrophages obtained from alcohol-intoxicated hemorrhaged animals was impaired when examined in vitro. We hypothesize that impaired neuroendocrine activation contributes to hemodynamic instability, which, in turn, prolongs tissue hypoperfusion and enhances risk for tissue injury. Specifically, the early dysregulation in counterregulatory responses is hypothesized to affect host defense mechanisms during the recovery period. We examined host response to systemic (cecal ligation and puncture) and localized (pneumonia) infectious challenge in animals recovering from hemorrhage during acute alcohol intoxication. Increased morbidity and mortality from infection were observed in alcohol-intoxicated hemorrhaged animals. Our results indicate that alcohol-induced alterations in early hemodynamic and neuroimmune responses to shock have an impact on susceptibility to an infectious challenge during the early recovery period.

Alcohol-induced suppression of lung chemokine production and the host defense response to Streptococcus pneumoniae

BACKGROUND

Acute alcohol intoxication impairs neutrophil migration in response to intrapulmonary infection with Streptococcus pneumoniae, the most common bacterial cause of pneumonia. Many of the same host defense functions that are impaired in the alcohol-intoxicated host are mechanistically associated with chemokines, a group of proinflammatory molecules that enhance neutrophil adhesion and direct neutrophil migration to sites of inflammation. The purpose of this study was to determine whether alcohol-induced chemokine suppression is responsible for impaired neutrophil recruitment into the lung during infection of the alcohol-intoxicated host.

METHODS

S. pneumoniae was administered (107 colony-forming units) intratracheally 30 min after intraperitoneal injection of 20% alcohol (5.5 g/kg) or saline. Four hours after bacterial challenge, bronchoalveolar lavage fluid (BALF) was collected, and the ability of BALF to induce neutrophil chemotaxis and adhesion molecule expression was measured by using chemotactic and flow cytometric assays. In another experiment, intratracheal challenge was performed by using recombinant macrophage inflammatory protein-2 (MIP-2), and BALF neutrophils were measured.

RESULTS

BALF MIP-2 and cytokine-induced neutrophil chemoattractant were decreased by alcohol, and BALF from alcohol-intoxicated animals had decreased chemotactic activity for neutrophils, as well as a decreased ability to up-regulate neutrophil adhesion molecule expression, compared with controls. This decreased chemotactic activity was significantly increased in the alcohol group by repletion of chemokines to control levels. Alcohol also suppressed neutrophil recruitment after intrapulmonary challenge with MIP-2, suggesting that mechanisms other than chemokine suppression contribute to the alcohol-induced effect.

CONCLUSIONS

At least two mechanisms, suppressed chemokine production and impaired neutrophil adhesion molecule expression, likely work in concert in the alcohol-intoxicated host to impair neutrophil adhesion and migration into the lung during pneumococcal infection. These alterations in neutrophil function likely increase the susceptibility of alcohol-consuming hosts to pneumonia.

The evaluation of reno- and hepatoprotective effects of huai-shan-yao (Rhizome Dioscoreae)

Huai-shan-yao (Chinese yam; Rhizome Dioscoreae) is a common food in China. In the present study, we evaluated the protective effects of the crude extract of huai-shan-yao on acute kidney and liver injuries in rats induced by ethanol. Results of pharmacological, biochemical and pathologic observations all showed that rats treated with the extract of huai-shan-yao had decreased damage in renal tubules as well as decreased inflammation in the central vein and necrosis in the liver tissue.

Host defense in respiratory infections

Respiratory defenses against infection involve a diverse and complex system. Mechanical barriers limit exposure of the respiratory tract to potential pathogenic organisms, whereas the mucociliary apparatus and cough reflexes work to expel any microbes that may bypass the initial defenses. When microorganisms have gained entry to the lower respiratory tract, the alveolar macrophage and recruited phagocytes may eliminate the culprits before active infection can be established. Only after the failure of the innate immune defenses is a specific immune response mounted. Examination of clinical defects in host defense allows one to understand the importance of the multitude of components of the lung's immune defense system.

The effects of granulocyte colony-stimulating factor and neutrophil recruitment on the pulmonary chemokine response to intratracheal endotoxin

Although G-CSF has been shown to increase neutrophil (polymorphonuclear leukocyte, PMN) recruitment into the lung during pulmonary infection, relatively little is known about the local chemokine profiles associated with this enhanced PMN delivery. We investigated the effects of G-CSF and PMN recruitment on the pulmonary chemokine response to intratracheal LPS. Rats pretreated twice daily for 2 days with an s.c. injection of G-CSF (50 microg/kg) were sacrificed at either 90 min or 4 h after intratracheal LPS (100 microg) challenge. Pulmonary recruitment of PMNs was not observed at 90 min post LPS challenge. Macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (CINC) concentrations in bronchoalveolar lavage (BAL) fluid were similar in animals pretreated with or without G-CSF at this time. G-CSF pretreatment enhanced pulmonary recruitment of PMNs (5-fold) and greatly reduced MIP-2 and CINC levels in BAL fluid at 4 h after LPS challenge. In vitro, the presence of MIP-2 and CINC after LPS stimulation of alveolar macrophages was decreased by coculturing with circulating PMNs but not G-CSF. G-CSF had no direct effect on LPS-induced MIP-2 and CINC mRNA expression by alveolar macrophages. Pulmonary recruited PMNs showed a significant increase in cell-associated MIP-2 and CINC. Cell-associated MIP-2 and CINC of circulating PMNs were markedly increased after exposure of these cells to the BAL fluid of LPS-challenged lungs. These data suggest that recruited PMNs are important cells in modulating the local chemokine response. G-CSF augments PMN recruitment and, thereby, lowers local chemokine levels, which may be one mechanism resulting in the subsidence of the host proinflammatory response.

Blood neutrophil functions and cytokine release in severe alcoholic hepatitis: effect of corticosteroids

BACKGROUND/AIMS

Several observations point to an important role of interactions between polymorphonuclear neutrophils and cytokines in severe alcoholic hepatitis. The polymorphonuclear neutrophil activation status and the local and systemic pro- and anti-inflammatory cytokine responses were quantified. The effect of corticosteroids, widely used in this setting, was evaluated using these parameters.

METHODS

We studied blood polymorphonuclear neutrophil functions in terms of L-selectin and beta2-integrin expression, H2O2 production and IL-8 and tumor necrosis factor alpha synthesis capacity. We also measured IL-8, tumor necrosis factor alpha and IL-10 plasma and liver tissue levels. Fifteen patients with alcoholic hepatitis were compared to 15 patients with alcoholic cirrhosis without alcoholic hepatitis, and to 10 healthy volunteers. The impact of a 28-day course of corticosteroids on blood neutrophils activation status and cytokine levels was evaluated in patients with alcoholic hepatitis.

RESULTS

Blood polymorphonuclear neutrophils were activated, as shown by increased H2O2 production (48+/-6 vs 29+/-6 MFI in healthy controls), and decreased L-selectin expression (300+/-61 vs 449+/-59 in healthy controls). Upon stimulation, polymorphonuclear neutrophils synthesized large amounts of IL-8 (21.7+/-9.2 ng/ml vs 8.8+/-10 ng/ml in healthy controls) and tumor necrosis factor alpha (524+/-132 pg/ml vs 79+/-144 pg/ml in healthy controls). Tumor necrosis factor alpha and IL-8 plasma and tissue levels were markedly increased as IL-10 was barely detectable in alcoholic hepatitis patients, compared to cirrhotic patients and healthy controls. During steroid therapy, plasma levels of the pro-inflammatory cytokine IL-8 fell as early as day 14, while levels of the anti-inflammatory cytokine IL-10 increased on day 21. Finally, polymorphonuclear neutrophil functions returned to normal after treatment.

CONCLUSION

Severe alcoholic hepatitis appears to be associated with polymorphonuclear neutrophil activation and an imbalance between pro- and anti-inflammatory cytokines; during steroid therapy a normalization of these parameters was observed.

Alcohol abuse, alcoholism, and damage to the immune system--a review

Chronic alcohol abuse exacts a major social and medical toll in the United States and other Western countries. One of the least appreciated medical complications of alcohol abuse is altered immune regulation leading to immunodeficiency and autoimmunity. The consequences of the immunodeficiency include increased susceptibility to bacterial pneumonia, tuberculosis, and other infectious diseases. In addition, the chronic alcoholic often has circulating autoantibodies, and recent investigations indicate that the most destructive complications of alcoholism, such as liver disease and liver failure, may have a component of autoimmunity. Current research on altered cytokine balance produced by alcohol is leading to new insights on the regulation of the immune system in the chronic alcoholic. There is also recent development of exciting new techniques designed to improve or restore immune function by manipulation of cytokine balance. Although much remains to be learned, both in the abnormalities produced by alcohol and in the techniques to reverse those abnormalities, current progress reflects a rapidly improving understanding of the basic immune disorders of the alcoholic.

Innate immunity, cytokines, and pulmonary host defense

Effective host defense against bacterial infection is dependent on the activation and recruitment of phagocytic cells. The initiation, maintenance, and resolution of this inflammatory response in the setting of bacterial pneumonia is dependent on the expression of cytokines. As the complexities of the host-pathogen interaction are further dissected and unraveled, immunologic manipulation of cytokine expression will likely become an important adjuvant therapy in the treatment of serious lung infections.