The role of chronic alcohol abuse in the development of acute respiratory distress syndrome in adults

Zinc deficiency mediates alcohol-induced alveolar epithelial and macrophage dysfunction in rats

Chronic alcohol abuse impairs both alveolar epithelial and macrophage function, and renders individuals susceptible to acute lung injury, pneumonia, and other serious lung diseases. Zinc deficiency, which is known to impact both epithelial and immune cell functions, is also associated with alcohol abuse. In this study, chronic alcohol ingestion (6 wk) in rats altered expression of key zinc transporters and storage proteins in the small intestine and the lung, and decreased zinc levels in the alveolar compartment. Zinc supplementation of alveolar epithelial monolayers derived from alcohol-fed rats in vitro, or of the diets of alcohol-fed rats in vivo, restored alveolar epithelial barrier function, and these improvements were associated with salutary changes in tight junction protein expression and membrane localization. In parallel, dietary zinc supplementation increased intracellular zinc levels, GM-CSF receptor expression, and bacterial phagocytic capacity in the alveolar macrophages of alcohol-fed rats. Together, these studies implicate zinc deficiency as a novel mechanism mediating alcohol-induced alveolar epithelial and macrophage dysfunction. Importantly, these findings argue that dietary supplementation can overcome alcohol-induced zinc deficiency and restore alveolar epithelial and macrophage function, and therefore could be an effective treatment for the susceptible alcoholic lung phenotype.

Alcohol primes the airway for increased interleukin-13 signaling

BACKGROUND

Using an experimental model of airway fibrosis following lung transplantation, we recently showed that chronic alcohol ingestion by donor rats amplifies airway fibrosis in the recipient. Associated with alcohol-mediated amplification of airway fibrosis is increased transforming growth factor beta-1(TGFbeta(1)) and alpha-smooth muscle actin expression. Other studies have shown that interleukin-13 (IL-13) modulates TGFbeta(1) signaling during experimentally-induced airway fibrosis. Therefore, we hypothesized that IL-13 is a component of alcohol-mediated amplification of pro-fibrotic mediators in the alcoholic lung.

METHODS

To test this hypothesis, we analyzed tracheal epithelial cells and type II alveolar cells from control- or alcohol-fed rats, alcohol-treated mouse lung fibroblasts, and human bronchial epithelial cells in vitro for expression of various components of the IL-13 signaling pathway. Signaling via the IL-13 pathway was assessed by measuring levels of phosphorylated signal transducers and activators of transcription-6 (STAT6). In addition, we performed heterotopic tracheal transplantation using control-fed and alcohol-fed donor rats and analyzed tracheal allografts for expression of components of the IL-13 signaling pathway by RT-PCR and immunocytochemical analyses.

RESULTS

Interleukin-13 expression was detected in type II alveolar epithelial cells and human bronchial epithelial cells, but not in lung fibroblasts. IL-13 expression was decreased in whole lung and type II cells in response to alcohol exposure. In all cell types analyzed, expression of IL-13 signaling receptor (IL-13R alpha(1)) mRNA was markedly increased. In contrast, mRNA and protein expression of the IL-13 decoy receptor (IL-13R alpha(2)) were decreased in all cells analyzed. Exposure to alcohol also increased STAT6 phosphorylation in response to IL-13 and lipopolysaccharide.

CONCLUSIONS

Data from multiple cell types in the pulmonary system suggest that IL-13 and its receptors play a role in alcohol-mediated activation of pro-fibrotic pathways. Taken together, these data suggest that alcohol primes the airway for increased IL-13 signaling and subsequent tissue remodeling upon injury such as transplantation.

Variation in the myosin light chain kinase gene is associated with development of acute lung injury after major trauma

BACKGROUND

Single nucleotide polymorphisms in the myosin light chain kinase (MYLK) gene have been implicated in the risk of sepsis-related acute lung injury and asthma. MYLK encodes protein isoforms involved in multiple components of the inflammatory response, including apoptosis, vascular permeability, and leukocyte diapedesis. We tested the association of MYLK gene variation in the development of acute lung injury in major trauma patients.

METHODS

We conducted a prospective cohort study of 273 subjects with major trauma (injury severity score > or = 16). All x-rays and clinical data were reviewed by three clinicians for acute lung injury classification. A total of 17 tagging single nucleotide polymorphisms in MYLK were genotyped. Single nucleotide polymorphisms were individually assessed at the genotype level, and multiple logistic regression models were used to adjust for baseline variables. Haplotype analyses of sliding windows including 2-5 single nucleotide polymorphisms were conducted.

RESULTS

Ninety-one of the 273 subjects (33%) met criteria for acute lung injury within 5 days of traumatic insult. Three informative MYLK coding single nucleotide polymorphisms were individually associated with acute lung injury, with two informative risk-conferring genotypes His21Pro (CC genotype, odds ratio = 1.87, 95% confidence interval 1.06-3.33; p = 0.022) and Pro147Ser (TT, odds ratio = 2.13, 95% confidence interval 1.14-4.10; p = 0.011) more frequent than the noninformative Thr335Thr CC genotype (odds ratio = 0.42, 95% confidence interval 0.20-0.85; p = 0.010). Each of these genotypic associations was more pronounced in African Americans with trauma. Multivariate analyses demonstrated the association of each MYLK single nucleotide polymorphism with acute lung injury to be independent of age, injury severity score, Acute Physiology and Chronic Health Evaluation III, and the mechanism of trauma. Finally, haplotype analyses revealed strong acute lung injury associations with 2-4 single nucleotide polymorphism haplotypes, all involving His21Pro (p < 0.008).

CONCLUSIONS

Three MYLK coding single nucleotide polymorphisms previously associated with sepsis-induced acute lung injury and severe asthma in African Americans were associated with acute lung injury development after trauma in African Americans, although effect directions differed. These results confirm our prior studies implicating MYLK as a susceptibility gene in a distinct acute lung injury subset other than sepsis.

Organ-specific inflammation following acute ethanol and burn injury

Clinical and experimental evidence demonstrates that ethanol exposure prior to injury alters local and systemic inflammatory responses, increasing morbidity and mortality. Moreover, the aberrant inflammatory responses can directly and indirectly lead to the poor prognosis after injury by altering leukocyte infiltration into the wound site and remote organs and by suppressing immunity leading to increased susceptibility to opportunistic infections. Recent studies from our laboratory have focused on inflammatory responses at the wound site and in other distal organs after exposure to acute ethanol and burn injury. This combined insult leads to increased mortality after dermal or intratracheal pseudomonas infection, relative to infected mice given ethanol or burn injury alone. The increased mortality in mice given ethanol and burn injury parallels elevated serum levels of proinflammatory cytokines, IL-6 and TNF-alpha, marked infiltration of leukocytes into the lung and gut, as well as immunosuppression at the sites of infection. Bacterial translocation from the gut is likely to be responsible, in part, for the aberrant accumulation of leukocytes in the lungs of ethanol-exposed, burn-injured mice. Additionally, other factors, such as expression of adhesion molecules, increased chemokine production, and leakiness of the vascular endothelium, may also be involved.

Pathogenesis of the systemic inflammatory syndrome and acute lung injury: role of iron mobilization and decompartmentalization

Changes in iron homeostatic responses routinely accompany infectious or proinflammatory insults. The systemic inflammatory response syndrome (SIRS) and the development of acute lung injury (ALI) feature pronounced systemic and lung-specific alterations in iron/heme mobilization and decompartmentalization; such responses may be of pathological significance for both the onset and progression of acute inflammation. The potential for excessive iron-catalyzed oxidative stress, altered proinflammatory redox signaling, and provision of iron as a microbial growth factor represent obvious adverse aspects of altered in vivo iron handling. The release of hemoglobin during hemolytic disease or surgical procedures such as those utilizing cardiopulmonary bypass procedures further impacts on iron mobilization, turnover, and storage with associated implications. Genetic predisposition may ultimately determine the extent to which SIRS and related syndromes develop in response to such changes. The design of specific therapeutic interventions based on endogenous stratagems to limit adverse aspects of altered iron handling may prove of therapeutic benefit for the treatment of SIRS and ALI.

Transfusion-related acute lung injury in the critically ill: prospective nested case-control study

RATIONALE

Acute lung injury (ALI) that develops 6 hours after transfusion (TRALI) is the leading cause of transfusion-related mortality. Several transfusion characteristics have been postulated as risk factors for TRALI, but the evidence is limited to retrospective studies.

OBJECTIVES

To compare patient and transfusion risk factors between patients who do and do not develop ALI.

METHODS

In this prospective cohort study, consecutive transfused critically ill patients were closely observed for development of ALI. Donor samples were collected from the transfusion bags. Risk factors were compared between patients who developed ALI after transfusion and transfused control patients, matched by age, sex, and admission diagnosis.

MEASUREMENTS AND MAIN RESULTS

Seventy-four of 901 transfused patients developed ALI within 6 hours of transfusion (8%). Compared with transfused control subjects, patients with ALI were more likely to have sepsis (37 vs. 22%, P = 0.016) and a history of chronic alcohol abuse (37 vs. 18%, P = 0.006). When adjusted for patient characteristics, transfusion of plasma from female donors (odds ratio [OR], 5.09; 95% confidence interval [95% CI], 1.37-18.85) rather than male donors (OR, 1.60; 95% CI, 0.76 to 3.37), number of pregnancies among the donors (OR, 1.19; 95% CI, 1.05 to 1.34), number of donor units positive for anti-granulocyte antibodies (OR, 4.85; 95% CI, 1.32-17.86) and anti-HLA class II antibodies (OR, 3.08; 95% CI, 1.15-8.25), and concentration of lysophosphatidylcholine in the donor product (OR, 1.69; 95% CI, 1.10 to 2.59) were associated with the development of ALI.

CONCLUSIONS

Both patient and transfusion risk factors determine the probability of ALI after transfusion. Transfusion factors represent attractive targets for the prevention of ALI.

Association of RBC Transfusion With Mortality in Patients With Acute Lung Injury

BACKGROUND

RBC transfusion has been associated with increased morbidity and mortality in a variety of clinical settings. We assessed the effect of RBC transfusion on in-hospital mortality in patients with acute lung injury (ALI).

METHODS

Cohort study of 248 consecutive patients with ALI. RBC transfusion was evaluated as both dichotomous and continuous variables, with outcome being in-hospital mortality adjusted for clinical confounders and length of total hospital stay.

RESULTS

Overall in-hospital mortality rate was 39.5%. Of these patients, 207 of 248 patients (83.5%) received > or = 1 U of packed RBCs. The transfusion of any packed RBCs was associated with an increased risk of death (adjusted odds ratio [OR], 3.12; 95% confidence interval [CI], 1.28 to 7.58; p < 0.001). The overall OR per unit was 1.06 (95% CI, 1.04 to 1.09; p < 0.001) in the complete multivariable model. Transfusion after ALI onset was associated with an adjusted OR of 1.13 (95% CI, 1.07 to 1.20; p < 0.001), while transfusion before ALI onset was not associated with higher risk. The adjusted OR per unit of nonleukoreduced RBC transfused was 1.14 (95% CI, 1.07 to 1.21; p < 0.001), while the adjusted OR for leukoreduced cells per unit transfused was 1.06 (95% CI, 1.03 to 1.09; p < 0.001).

CONCLUSIONS

Transfusion of RBCs in patients with ALI was associated with increased in-hospital mortality. This risk occurred with RBC transfusion after the onset of ALI, and was greater for nonleukoreduced than for leukoreduced RBCs. Aggressive transfusion strategies in patients with established ALI should be questioned, pending further study.

Alcohol ingestion by donors amplifies experimental airway disease after heterotopic transplantation

RATIONALE

Obliterative bronchiolitis (OB) after lung transplantation is triggered by alloimmunity, but is ultimately mediated by transforming growth factor (TGF)-beta(1)-dependent airway fibrosis.

OBJECTIVES

Chronic alcohol use increases TGF-beta(1) expression and renders the lung susceptible to injury. Therefore, we hypothesized that donor alcohol abuse could prime the lung allograft for OB, as many organ donors have a history of alcohol abuse.

METHODS

Tracheas from control and alcohol-fed rats (8 wk) were heterotopically transplanted into recipients with varying degrees of alloimmune mismatch and analyzed for obliterative airway disease severity on Postoperative Day 21.

MEASUREMENTS AND MAIN RESULTS

Although donor alcohol ingestion did not increase the number of antigen-presenting cells or infiltrating lymphocytes, it nevertheless increased allograft lumenal collagen content fourfold compared with allografts from control donors. In parallel, alcohol increased TGF-beta(1) and alpha-smooth muscle actin expression in allografts. Alcohol amplified airway disease even in isografts with minor alloimmune mismatches. In contrast, it did not cause any airway disease in isografts in a pure isogenic background, suggesting that a minimal alloimmune response is necessary to trigger alcohol-induced airway fibrosis.

CONCLUSIONS

Although alloimmune inflammation is required to initiate airway disease, alcohol primes the allograft for greater TGF-beta(1) expression, myofibroblast transdifferentiation, and fibrosis than by alloimmune inflammation alone. This has serious clinical implications, as many lung donors have underlying alcohol abuse that may prime the allograft recipient for subsequent OB.

Epidemiology of sepsis: race, sex, and chronic alcohol abuse

The annual incidences of severe sepsis in several industrialized nations have recently been reported to be 50-100 cases per 100,000 persons. These numbers exceed the estimated rates for other diseases that hold a heightened public awareness, including breast cancer and acquired immune deficiency syndrome. There are also sex and race differences in the incidence of sepsis. Men are more likely than women to develop sepsis, with a mean annual relative risk of 1.28. Nonwhites are nearly twice as likely to develop sepsis as whites. These race and sex disparities in the incidence of sepsis are likely explained by differences in a variety of factors, including the presence of comorbid conditions. For example, chronic alcohol abuse is associated with a persistent fever, delayed resolution of symptoms, increased rates of bacteremia, increased use of intensive care, prolonged duration of hospital stay, and increased cost of hospitalization for infected patients.

Acute lung injury and the acute respiratory distress syndrome: a clinical review

Acute respiratory distress syndrome and acute lung injury are well defined and readily recognised clinical disorders caused by many clinical insults to the lung or because of predispositions to lung injury. That this process is common in intensive care is well established. The mainstay of treatment for this disorder is provision of excellent supportive care since these patients are critically ill and frequently have coexisting conditions including sepsis and multiple organ failure. Refinements in ventilator and fluid management supported by data from prospective randomised trials have increased the methods available to effectively manage this disorder.

Functional polymorphisms in the transcription factor NRF2 in humans increase the risk of acute lung injury

We recently used positional cloning to identify the transcription factor Nrf2 (NF-E2 related factor 2) as a susceptibility gene in a murine model of oxidant-induced acute lung injury (ALI). NRF2 binds to antioxidant response elements (ARE) and up-regulates protective detoxifying enzymes in response to oxidative stress. This led us to investigate NRF2 as a candidate susceptibility gene for risk of development of ALI in humans. We identified multiple single nucleotide polymorphisms (SNPs) by resequencing NRF2 in ethnically diverse subjects, and one (-617 C/A) significantly (P<0.001) diminished luciferase activity of promoter constructs containing the SNP and significantly decreased the binding affinity (P<0.001) relative to the wild type at this locus (-617 CC). In a nested case-control study, patients with the -617 A SNP had a significantly higher risk for developing ALI after major trauma (OR 6.44; 95% CI 1.34, 30.8; P=0.021) relative to patients with the wild type (-617 CC). This translational investigation provides novel insight into the molecular mechanisms of susceptibility to ALI and may help to identify patients who are predisposed to develop ALI under at risk conditions, such as trauma and sepsis. Furthermore, these findings may have important implications in other oxidative stress related illnesses.

Alcohol dependence is independently associated with sepsis, septic shock, and hospital mortality among adult intensive care unit patients

OBJECTIVE

To determine the association between alcohol dependence (alcoholism not in remission and/or alcohol withdrawal) and sepsis, septic shock, and hospital mortality among intensive care unit (ICU) patients.

DESIGN

Retrospective cohort study.

SETTING

Two ICUs in an urban hospital.

PATIENTS

Patients included 11,651 adult admissions to Denver Health Medical Center from January 1, 1999, to December 31, 2004, with >or=1 ICU day.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of first admissions appearing in the data set (n=9,981), 1,222 (12.2%) had a diagnosis consistent with alcohol dependence. These patients had higher rates of sepsis (12.9% vs. 7.6%, p<.001), organ failure (67.3% vs. 45.8%, p<.001), septic shock (3.6% vs. 2.1%, p=.001), and hospital mortality (9.4% vs. 7.5%, p=.022) on unadjusted analyses. Patients with alcohol dependence also had fewer hospital-free days. After adjustment for factors with known association with sepsis, alcohol dependence was associated with sepsis. This association was modified if the patient received (adjusted odds ratio, 0.92; 95% confidence interval, 0.65-1.31) or did not receive (adjusted odds ratio, 1.91; 95% confidence interval, 1.49-2.44) red cell transfusions. A general predisposition to infections mediated some, but not all, of this association. Results were similar when repeat admissions were included in the analysis. Alcohol dependence was also associated with septic shock and hospital mortality in multivariable analyses. Among those with liver disease and sepsis, alcohol dependence was associated with more than two-fold increased risk-adjusted odds of hospital mortality (adjusted odds ration, 2.31; 95% confidence interval, 1.26-4.24). Similarly, sepsis and liver disease carried higher odds of death for alcohol-dependent patients than for those without alcohol dependence.

CONCLUSIONS

Alcohol dependence is independently associated with sepsis, septic shock, and hospital mortality among ICU patients. The underlying mechanisms of this association require exploration, as an increased rate of infections mediated some, but not all, of this association.

Epidemiology and Outcomes of Acute Lung Injury

Acute lung injury (ALI) and its presentation with more severe hypoxemia, the ARDS, is a challenging entity for clinical investigation because, like many critical illness syndromes, it lacks an accepted diagnostic test and relies on a constellation of clinical findings for diagnosis. Despite these barriers, there have been important advances in the clinical and population epidemiology of ALI. This article will review recent studies of the incidence, diagnosis, etiologic and prognostic factors, relevant disease subsets, mortality, and long-term outcomes of ALI. A detailed understanding of the epidemiology and outcomes of ALI is essential for future research on mechanisms of both the acute presentation and long-term sequelae, for designing studies to identify genetic risk factors for developing ALI, and to develop strategies to treat or prevent the morbidity encountered by survivors.

The alcoholic lung: epidemiology, pathophysiology, and potential therapies

Epidemiological evidence gathered only in the past decade reveals that alcohol abuse independently increases the risk of developing the acute respiratory distress syndrome by as much as three- to fourfold. Experimental models and clinical studies are beginning to elucidate the mechanisms underlying this previously unrecognized association and are revealing for the first time that chronic alcohol abuse causes discrete changes, particularly within the alveolar epithelium, that render the lung susceptible to acute edematous injury in response to sepsis, trauma, and other inflammatory insults. Recent studies in relevant animal models as well as in human subjects are identifying common mechanisms by which alcohol abuse targets both the alveolar epithelium and the alveolar macrophage, such that the risks for acute lung injury and pulmonary infections are inextricably linked. Specifically, chronic alcohol ingestion decreases the levels of the antioxidant glutathione within the alveolar space by as much as 80-90%, and, as a consequence, impairs alveolar epithelial surfactant production and barrier integrity, decreases alveolar macrophage function, and renders the lung susceptible to oxidant-mediated injury. These changes are often subclinical and may not manifest as detectable lung impairment until challenged by an acute insult such as sepsis or trauma. However, even otherwise healthy alcoholics have evidence of severe oxidant stress in the alveolar space that correlates with alveolar epithelial and macrophage dysfunction. This review focuses on the epidemiology and the pathophysiology of alcohol-induced lung dysfunction and discusses potential new treatments suggested by recent experimental findings.

Alcohol abuse in the critically ill patient

Alcohol abuse and dependence disorders are common in the 10% of hospitalised patients who need admission to the intensive care unit (ICU), but these disorders are often undiagnosed. The systemic effects from the excessive use of alcohol increase susceptibility to, or directly cause various important disorders in the critically ill. Early recognition of alcohol abuse and dependence is necessary and should prompt consideration of several alcohol-specific diagnoses that have important prognostic and therapeutic implications for these patients. We discuss the use of screening tests to improve the identification of alcohol abuse and dependence disorders, the epidemiology and pathogenesis of important alcohol-related disorders, differences in the presentation of several common alcohol-related diagnoses in the ICU, and important alcohol-specific therapies.

Glutathione availability modulates alveolar macrophage function in the chronic ethanol-fed rat

We have previously demonstrated that chronic alcohol exposure decreases glutathione in the alveolar space. Although alcohol use is associated with decreased alveolar macrophage function, the mechanism by which alcohol impairs macrophage phagocytosis is unknown. In the current study, we examined the possibility that ethanol-induced alveolar macrophage dysfunction was secondary to decreased glutathione and subsequent chronic oxidative stress in the alveolar space. After 6 wk of ethanol ingestion, oxidant stress in the alveolar macrophages was evidenced by a 30-mV oxidation of the GSH/GSSG redox potential (P <or= 0.05). For control macrophages, approximately 80% internalized fluorescent Staphylococcus aureus were added in vitro. In contrast, only 20% of the macrophages from the ethanol-fed rats were able to bind and internalize fluorescent S. aureus. This ethanol-induced decreased capacity for phagocytosis was paralleled by increased apoptosis. When added to the ethanol diet, the glutathione precursors procysteine or N-acetyl cysteine normalized glutathione and oxidant stress in the epithelial lining fluid as well as the alveolar macrophages to control values. This attenuation of oxidant stress was associated with normalization of macrophage phagocytosis and viability. These results suggested that decreased glutathione availability in the alcoholic lung contribute to alveolar macrophage dysfunction via oxidative stress, resulting in not only decreased function but decreased viability.

GM-CSF receptor expression and signaling is decreased in lungs of ethanol-fed rats

Alcohol abuse dramatically increases the risk of acute lung injury. In an experimental rat model of ethanol-mediated susceptibility to lung injury, recombinant granulocyte/macrophage colony-stimulating factor (GM-CSF) restored alveolar epithelial barrier function both in vitro and in vivo, even during acute endotoxemia. These findings suggested that the alveolar epithelium, which secretes GM-CSF into the airway where it is required for alveolar macrophage maturation, likewise responds to GM-CSF priming in a receptor-mediated manner. In this study we determined that both the GM-CSF receptor alpha- and beta-subunits (GM-CSFRalpha and GM-CSFRbeta) are expressed throughout the rat airway epithelium and that this expression was significantly decreased in the alveolar epithelium following chronic ethanol ingestion (6 wk). In parallel, PU.1, the master transcription factor for GM-CSF signaling in hematopoietic cells, is also expressed in alveolar epithelial cells, and ethanol ingestion likewise decreased PU.1 protein expression and nuclear binding in the alveolar epithelium. Finally, GM-CSF signaling as reflected by PU.1 expression and nuclear binding was restored with recombinant GM-CSF treatment in vitro. We conclude that chronic ethanol ingestion decreases GM-CSF receptor expression and signaling in the lung epithelium. Consequently, we speculate that dampening of GM-CSF stimulation of the alveolar epithelium is responsible at least in part for the diverse functional defects that characterize the alcoholic lung and could be a therapeutic target in acute lung injury.

Effects of acute ethanol administration on LPS-induced expression of cyclooxygenase-2 and inducible nitric oxide synthase in rat alveolar macrophages

BACKGROUND

Activation of alveolar macrophages acts as a primary defense mechanism of lung with immunologic and inflammatory processes. Incidence of respiratory distress syndrome (ARDS) has been reported to be higher in alcoholics than that in nonalcoholics. Both cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) are induced by inflammatory stimuli such as LPS and cytokines and are involved in host defense. COX-2 and iNOS have been reported to play important roles in pathophysiology of ARDS. The aim of the present study was to elucidate whether acute ethanol administration to rats affects on COX-2 and iNOS expression in isolated alveolar macrophages.

METHODS

Ethanol (4.5 g per kg body weight as a 20% solution) was intraperitoneally injected to male Wistar rats. At 2.5 hrs after the injection, alveolar macrophages were collected from rats by bronchoalveolar lavage and were stimulated with lipopolysaccharide (LPS, 1 mug/ml). Expression of COX-2 and iNOS and activation of MAPKs was evaluated by Western blotting.

RESULTS

In alveolar macrophages isolated from ethanol-treated rats, LPS-stimulated production of both prostaglandin E2 and nitrite was significantly lower than that in macrophages isolated from vehicle-treated control rats. LPS-induced expression of both COX-2 and iNOS was significantly lower in macrophages from ethanol-treated rats than that in macrophages from the control rats, while expression of beta-actin was not different in these groups. LPS increased phosphorylation of both extracellular signal-regulated protein kinase (ERK) and p38 mitogen-activated protein kinase (MAPK). The levels of phosphorylated ERK and p38 were significantly lower in macrophages from ethanol-treated rats compared with those from the control rats. Treatment of macrophages with ethanol (100 - 400 mM) in vitro significantly inhibited expression of COX-2 in a concentration-dependent manner, while only a high concentration (400 mM) of ethanol significantly inhibited expression of iNOS. Ethanol also inhibited COX-2 expression in the presence of Tiron. Expression of COX-2 and iNOS was significantly inhibited by U0126 but not by SB203580.

CONCLUSION

In rat alveolar macrophages, LPS-induced expression of COX-2 and iNOS is mediated by ERK MAPK but not by p38 MAPK. Acute ethanol administration to rats attenuates induction of both COX-2 and iNOS in alveolar macrophages by inhibiting phosphorylation of ERK.

Pharmacological therapy for acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is an Inflammatory process caused by a variety of direct and indirect injuries to the lungs. Despite improvements in supportive care and advances in ventilator management, mortality in patients with ARDS remains high. Multiple pharmacological interventions have been investigated but have not shown improved survival. Clinical trials using corticosterolds, prostaglandins, nitric oxide, prostacyclin, surfactant, lisofylline, ketoconazole, N-acetylcystelne, and fish oil have been unable to show a statistically significant Improvement in patient mortality. As more is understood about the pathophyslology of ARDS, treatment strategies such as increasing alveolar fluid clearance through activation of sodium channels, enhancing repair of alveolar epithelium with growth factors, inhibiting fibrin deposition, blocking proinflammatory transcription factors, preventing the effect of potent vasocontrictors such as endothelin, and using antibodies against key inflammatory cytokines are being explored. This review focuses on the pharmacological treatments studied clinically, proposed reasons for their lack of success, and new concepts emerging in ARDS therapy.

[Postoperative pneumonia: nosocomial, predictable, iatrogenic, preventable or not?]

We report the case of a 52-year-old man, ASA 3-4, malnourished, heavy smoker and drinker at the stage of chronic obstructive pulmonary disease and cirrhosis. The postoperative course of a cervical cancer surgery was complicated by a pneumonia with fatal outcome in the intensive care unit. Taking into account the patient's history and surgical requirements, this nosocomial infection did not appear easily preventable. The multiple risk factors and the few preventive measures usable were analyzed. In this context, the media and legal trend to make the doctors responsible for the nosocomial infections should be revised.

Alcohol reversibly disrupts TNF-alpha/TACE interactions in the cell membrane

Background

Alcohol abuse has long been known to adversely affect innate and adaptive immune responses and pre-dispose to infections. One cellular mechanism responsible for this effect is alcohol-induced suppression of TNF-α (TNF) by mononuclear phagocytes. We have previously shown that alcohol in part inhibits TNF-α processing by TNF converting enzyme (TACE) in human monocytes. We hypothesized that the chain length of the alcohol is critical for post-transcriptional suppression of TNF secretion.

Methods

Due to the complex transcriptional and post-transcriptional regulation of TNF in macrophages, to specifically study TNF processing at the cell membrane we performed transient transfections of A549 cells with the TNF cDNA driven by the heterologous CMV promoter. TNF/TACE interactions at the cell surface were assessed using fluorescent resonance energy transfer (FRET) microscopy.

Results

The single carbon alcohol, methanol suppressed neither TNF secretion nor FRET efficiency between TNF and TACE. However, 2, 3, and 4 carbon alcohols were potent suppressors of TNF processing and FRET efficiency. The effect of ethanol, a 2-carbon alcohol was reversible.

Conclusion

These data show that inhibition of TNF-α processing by acute ethanol is a direct affect of ethanol on the cell membrane and is reversible upon cessation or metabolism.

Alcohol-induced lung damage and increased oxidative stress

BACKGROUND

Alcohol-induced lung damage may be associated with increased oxidative stress.

OBJECTIVE

Our aim was to investigate alcohol-induced changes in the biochemistry and histopathology of the lung.

METHODS

Rats were divided into two groups, a control group and an ethanol group. The ethanol group received 2 g/kg ethanol (total: 3 ml) intraperitoneally. The controls were given the same amount of saline via the same route. Three hours later, the rats were sacrificed, and blood and lung tissue samples were obtained. Oxidative stress was assessed by measuring the levels of erythrocyte reduced glutathione (GSH), tissue malondialdehyde (MDA), myeloperoxidase (MPO) and Na(+)-K(+) ATPase. Histopathologic evaluation of the lung tissues was also performed.

RESULTS

In the ethanol group, serum and tissue MDA levels and MPO activities were increased (p = 0.007, p = 0.001 and p = 0.000), and lung tissue Na(+)-K(+) ATPase activities and erythrocyte GSH were decreased (p = 0.001 and p = 0.000) compared to the controls. Histopathologic examination demonstrated alveolocapillary thickening, alveolar degeneration, leukocyte infiltration and erythrocyte extravasation in the lungs of the ethanol group (p < 0.05).

CONCLUSION

These results suggest that high-dose acute alcohol administration aggravates systemic and local oxidative stress leading to acute lung injury, ranging from mild pulmonary dysfunction to severe lung injury. It should be borne in mind that rapid onset of the acute respiratory distress syndrome (ARDS) may also be due to increased oxidative stress following alcohol abuse, especially when ischemic disturbances, e.g. coronary heart disease, acute ischemia of the extremities and traumatic accidents, are concomitantly present. Therefore, precautions against ARDS may prevent morbidity and mortality in alcohol-induced lung damage in at-risk patients.

Alcohol abuse and acute lung injury: epidemiology and pathophysiology of a recently recognized association

Alcohol is the most commonly used and abused drug in the United States. The deleterious health effects of alcohol can be attributed both to its acute intoxicating effects, which result in temporary impairment of judgment and motor skills, and to its more chronic and toxic effects on the liver, pancreas, heart, and brain, all of which may result in irreversible organ damage. Although recognized for more than a century as a major risk factor for pneumonia, alcohol abuse was until recently perceived to have no significant effects on lung structure and/or function. However, within the past decade, epidemiologic studies have revealed that alcohol abuse independently increases the risk of acute respiratory distress syndrome (ARDS) two- to fourfold in patients with sepsis or trauma and may play a role in ARDS pathogenesis in as many as half of all patients with the syndrome. Although alcohol abuse alone does not cause acute lung injury, it renders the lung susceptible to dysfunction in response to the inflammatory stresses of sepsis, trauma, and other clinical conditions recognized to cause ARDS. Recent investigations in both animal models of chronic ethanol ingestion and in human subjects with a history of alcohol abuse have explored this previously unrecognized connection between alcohol and acute lung injury and have uncovered multiple derangements, which we now characterize as the "alcoholic lung." This review summarizes the epidemiologic association between alcohol abuse and acute lung injury and the recent experimental findings that are unraveling the underlying pathophysiology.

ARDS Diagnosis and Management

Acute Respiratory Distress Syndrome (ARDS), an intense form of hypoxemic respiratory failure, may be one of the most elusive diagnoses encountered in the intensive care unit. Increasing the knowledge base of the critical care nurse is imperative to prevent and diagnose ARDS, as well as to generate and implement evidence-based clinical interventions. This article presents a thorough examination of the many facets of ARDS, including its definition, etiology, pathophysiology, presentation, diagnosis, and management.

Clinical predictors of and mortality in acute respiratory distress syndrome: Potential role of red cell transfusion*

OBJECTIVE

Clinical predictors for acute respiratory distress syndrome (ARDS) have been studied in few prospective studies. Although transfusions are common in the intensive care unit, the role of submassive transfusion in non-trauma-related ARDS has not been studied. We describe here the clinical predictors of ARDS risk and mortality including the role of red cell transfusion.

DESIGN

Observational prospective cohort.

SETTING

Intensive care unit of Massachusetts General Hospital.

PATIENTS

We studied 688 patients with sepsis, trauma, aspiration, and hypertransfusion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred twenty-one (32%) subjects developed ARDS with a 60-day mortality rate of 46%. Significant predictors for ARDS on multivariate analyses included trauma (adjusted odds ratio [ORadj] 0.22, 95% confidence interval [CI] 0.09-0.53), diabetes (ORadj 0.58, 95% CI 0.36-0.92), direct pulmonary injury (ORadj 3.78, 95% CI 2.45-5.81), hematologic failure (ORadj 1.84, 95% CI 1.05-3.21), transfer from another hospital (ORadj 2.08, 95% CI 1.33-3.25), respiratory rate >33 breaths/min (ORadj 2.39, 95% CI 1.51-3.78), hematocrit >37.5% (ORadj 1.77, 95% CI 1.14-2.77), arterial pH <7.33 (ORadj 2.00, 95% CI 1.31-3.05), and albumin </=2.3 g/dL (ORadj 1.80, 95% CI 1.18-2.73). Packed red blood cell transfusion was associated with ARDS (ORadj 1.52, 95% CI 1.00-2.31, p = .05). Significant predictors for mortality in ARDS included age (ORadj 1.96, 95% CI 1.50-2.53), Acute Physiology and Chronic Health Evaluation III score (ORadj 1.78, 95% CI 1.16-2.73), trauma (ORadj 0.075, 95% CI 0.006-0.96), corticosteroids before ARDS (ORadj 4.65, 95% CI 1.47-14.7), and arterial pH <7.22 (ORadj 2.32, 95% CI 1.02-5.25). Packed red blood cell transfusions were associated with increased mortality in ARDS (ORadj 1.10 per unit transfused; 95% CI 1.04-1.17) with a significant dose-dependent response (p = .02).

CONCLUSIONS

Important predictors for the development of and mortality in ARDS were identified. Packed red blood cell transfusion was associated with an increased development of and increased mortality in ARDS.

Psychosocial function after hematopoietic stem cell transplantation

The authors report on a prospective cohort study of patients with chronic myelogenous leukemia undergoing allogeneic hematopoietic stem cell transplantation. The purpose was to evaluate the progression of quality of life and mood, as well as patterns of alcohol consumption, a behavior with potential adverse health consequences. Of the 84 subjects who completed serial measures and other interviews at admission for hematopoietic stem cell transplantation and 6-month follow-up, 75 provided data 12 months later The main findings of this study were that quality of life improves, measures of depressive symptoms decline, and patients drink less alcohol overall. Time was the most important variable accounting for these changes.

Angiotensin II mediates glutathione depletion, transforming growth factor-beta1 expression, and epithelial barrier dysfunction in the alcoholic rat lung

Alcohol abuse markedly increases the risk of sepsis-mediated acute lung injury. In a rat model, ethanol ingestion alone (in the absence of any other stress) causes pulmonary glutathione depletion, increased expression of transforming growth factor-beta1 (TGF-beta1), and alveolar epithelial barrier dysfunction, even though the lung appears grossly normal. However, during endotoxemia, ethanol-fed rats release more activated TGF-beta1 into the alveolar space where it can exacerbate epithelial barrier dysfunction and lung edema. Ethanol ingestion activates the renin-angiotensin system, and angiotensin II is capable of inducing oxidative stress and TGF-beta1 expression. We determined that lisinopril, an angiotensin-converting enzyme inhibitor that decreases angiotensin II formation, limited lung glutathione depletion, and treatment with either lisinopril or losartan, a selective angiotensin II type 1 receptor blocker, normalized TGF-beta1 expression. The glutathione precursor procysteine also prevented TGF-beta1 expression, suggesting that TGF-beta1 may be induced indirectly by angiotensin II-mediated oxidative stress and glutathione depletion. Importantly, lisinopril treatment normalized barrier function in alveolar epithelial cell monolayers from ethanol-fed rats, and treatment with either lisinopril or losartan normalized alveolar epithelial barrier function in ethanol-fed rats in vivo, as reflected by lung liquid clearance of an intratracheal saline challenge, even during endotoxemia. In parallel, lisinopril treatment limited TGF-beta1 protein release into the alveolar space during endotoxemia. Together, these results suggest that angiotensin II mediates oxidative stress and the consequent TGF-beta1 expression and alveolar epithelial barrier dysfunction that characterize the alcoholic lung.

Acute Respiratory Distress Syndrome

Acute lung injury is a syndrome diagnosed clinically and is one of the most common causes of respiratory failure seen in the intensive care unit. A consensus definition of this and its more severe form, acute respiratory distress syndrome (ARDS), has allowed for better consistency in determining the epidemiology and facilitates consistent clinical trial design to better find therapies to treat or prevent it. Patients who present with ARDS usually show signs of tachpnea or dyspnea and have underlying conditions that promote inflammatory responses. The pathogenesis involves an inflammatory insult that eventually destroys the pulmonary capillary vasculature as well as alveoli. Pathophysiologically, the patient with ARDS may progress through as many as 3 phases: exudative, proliferative, and fibrotic. Treatment options can be either nonpharmacologic or pharmacologic and are limited. Ventilator strategies such as low-tidal-volume ventilation have improved outcomes in these patients, while corticosteroid use is not as established to provide morbidity or mortality benefit. Other therapies have been investigated with inconclusive or disappointing results for the treatment of this fatal syndrome.

Ethanol stimulates the expression of fibronectin in lung fibroblasts via kinase-dependent signals that activate CREB

Ethanol renders the lung susceptible to acute lung injury in the setting of insults such as sepsis. The mechanisms mediating this effect are unknown, but activation of tissue remodeling is considered key to this process. We found that chronic ethanol ingestion in rats increased the expression of fibronectin, a matrix glycoprotein implicated in acute lung injury. In cultured NIH/3T3 cells and in primary rat and mouse lung fibroblasts, ethanol induced fibronectin mRNA and protein expression in a dose- and time-dependent fashion. The effect of ethanol was prevented by inhibitors of protein kinase C and mitogen-activated protein kinases and was associated with the phosphorylation and increased DNA binding of the transcription factor cAMP response element binding protein, followed by increased transcription of the fibronectin gene. Fibroblasts were found to express alpha(7) nicotinic acetylcholine receptor (nAChR), and ethanol induction of fibronectin was abolished by alpha-bungarotoxin and methyllcaconitine, inhibitors of alpha(7) nAChRs. However, ethanol was able to induce fibronectin mRNA and protein in primary lung fibroblasts isolated from alpha(7) nAChR knockout mice. The ethanol-induced fibronectin response was dependent on ethanol metabolism since 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, abolished the effect and acetaldehyde induced it. These observations suggest that ethanol or ethanol metabolites stimulate lung fibroblasts to produce fibronectin by inducing specific signals transmitted via nAChRs independent of the alpha(7-)subunit, and this might represent a mechanism by which ethanol renders the lung susceptible to acute lung injury.

Ventilator-associated lung injury in patients without acute lung injury at the onset of mechanical ventilation

OBJECTIVE

Although ventilation with small tidal volumes is recommended in patients with established acute lung injury, most others receive highly variable tidal volume aimed in part at normalizing arterial blood gas values. We tested the hypothesis that acute lung injury, which develops after the initiation of mechanical ventilation, is associated with known risk factors for ventilator-induced lung injury such as ventilation with large tidal volume.

DESIGN

Retrospective cohort study.

SETTING

Four intensive care units in a tertiary referral center.

PATIENTS

Patients who received invasive mechanical ventilation for > or = 48 hrs between January and December 2001.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The main outcome of interest, acute lung injury, was assessed by independent review of daily digital chest radiographs and arterial blood gases. Ventilator settings, hemodynamics, and acute lung injury risk factors were extracted from the Acute Physiology and Chronic Health Evaluation III database and the patients' medical records. Of 332 patients who did not have acute lung injury from the outset, 80 patients (24%) developed acute lung injury within the first 5 days of mechanical ventilation. When expressed per predicted body weight, women were ventilated with larger tidal volume than men (mean 11.4 vs. 10.4 mL/kg predicted body weight, p <.001) and tended to develop acute lung injury more often (29% vs. 20%, p =.068). In a multivariate analysis, the main risk factors associated with the development of acute lung injury were the use of large tidal volume (odds ratio 1.3 for each mL above 6 mL/kg predicted body weight, p <.001), transfusion of blood products (odds ratio, 3.0; p < 0.001), acidemia (pH < 7.35; odds ratio, 2.0; p =.032) and a history of restrictive lung disease (odds ratio, 3.6; p =.044).

CONCLUSIONS

The association between the initial tidal volume and the development of acute lung injury suggests that ventilator-associated lung injury may be an important cause of this syndrome. Height and gender should be considered when setting up the ventilator. Strong consideration should be given to limiting large tidal volume, not only in patients with established acute lung injury but also in patients at risk for acute lung injury.

Predictors of 1-Year Survival Assessed at the Time of Bone Marrow Transplantation

The purpose of this prospective cohort study was to identify pretransplant and transplant predictors of 1-year survival after allogeneic hematopoietic stem cell transplantation (HSCT) for chronic myelogenous leukemia. Psychosocial and behavioral variables such as alcohol abuse and cigarette smoking were systematically assessed at the time of HSCT with structured diagnostic instruments. A total of 114 patients participated, with an overall 1-year survival rate of 66%. Lifetime alcohol and other substance use, cigarette smoking, depression, and quality of life prior to transplant were not found to affect 1-year survival. However, other clinical variables prior to transplant and once transplant occurred were found to predict survival.

Effect of prostaglandin E receptor subtype EP4 selective agonist on the secretion of tumor necrosis factor-alpha by macrophages in acute ethanol-loaded rats

BACKGROUND

It is suggested that endotoxin and proinflammatory cytokines play an important role in the development and progression of alcoholic liver disease. Recently, a prostaglandin receptor subtype EP4 agonist with cytoprotective effect has been developed. We examined the efficacy of an EP4 agonist ONO-AE1-437 on tumor necrosis factor-alpha (TNF-alpha) secretion of Kupffer cells, splenic macrophages, and alveolar macrophages in acute ethanol-loaded rats.

METHODS

Kupffer cells, splenic macrophages, and alveolar macrophages were isolated from control and acute ethanol-loaded rats (5 mg/g body weight of ethanol, intraperitoneally). After the preculture in the medium that containing 0, 0.1, 1, 10, or 100 nmol/liter of ONO-AE1-437, TNF-alpha secretion of these cells stimulated by 100 ng/ml of endotoxin was determined for 3 hr.

RESULTS

The amount of TNF-alpha secreted from alveolar macrophages was largest in both the control and the acute ethanol-loaded rats. Acute ethanol load enhances TNF-alpha secretion of splenic macrophages. The addition of ONO-AE1-437 significantly inhibited TNF-alpha secretion of Kupffer cells and splenic macrophages in both the control and the acute ethanol-loaded rats. Alveolar macrophages were less affected.

CONCLUSIONS

An EP4 agonist ONO-AE1-437 suppresses excess TNF-alpha secretion from macrophages and seems promising for future trial in patients with severe alcoholic hepatitis.

Admission lactate level and the APACHE II score are the most useful predictors of prognosis following torso trauma

BACKGROUND

Markers of dysoxic metabolism and scoring systems for triage have been widely used in critically injured patients. However, so far, no model is sufficiently reliable to predict the outcome in trauma victims. The purposes of the present study, therefore, were to determine whether a correlation exits between the main trauma scoring systems and the markers of dysoxic metabolism. Moreover, to assess if any of the admission parameters can be used to indicate outcome.

METHODS

Sixty-four patients were included in this study. Admission data, including arterial lactate level, base deficit (BD), pH, revised trauma score (RTS), injury severity score (ISS), shock index (SI), and Acute Physiology and Chronic Health Evaluation (APACHE II), were collected and analysed by logistic regression analysis. Degree of association between continuous variables were calculated by either Pearson's or Spearman's correlation coefficient, where applicable. The dependence of lactate on two or more other variables was evaluated by multiple linear regression analysis.

RESULTS

Logistic regression analysis showed that the fatal outcome following major torso trauma was principally associated with the APACHE II score and lactate. The specificity and the sensitivity of this logistic regression model was 94.6 and 79.2%, respectively. According to standardised linear regression coefficients, BD was the best single predictor of lactate, and APACHE II added a small amount of predictive power. The proportion of total variation in lactate level explained by base deficit, APACHE II and age is R2=85.2%.

CONCLUSION

APACHE II score and the arterial lactate level are the most important determinants of clinical outcome in critically injured patients. A correlation exits between lactate and APACHE II and between lactate and base deficit.

Transforming Growth Factor β1Expression and Activation Is Increased in the Alcoholic Rat Lung

Alcohol abuse increases the incidence of acute respiratory distress syndrome more than threefold in patients with septic shock. We have shown that chronic ethanol ingestion in a rat model impairs alveolar epithelial barrier function and enhances lung injury during sepsis. We speculated that transforming growth factor beta(1) (TGFbeta(1)), a pluripotent cytokine implicated in models of epithelial barrier disruption and lung injury, could mediate alveolar epithelial injury in the alcoholic lung. We report that chronic ethanol ingestion (6 weeks) in rats increased both TGFbeta(1) mRNA and protein tissue expression (p < 0.05), but alone did not induce the release of TGFbeta(1) into the alveolar space. However, during endotoxemia, ethanol-fed rats released fivefold more TGFbeta(1) protein (by ELISA, p < 0.05) into the alveolar space than control-fed rats. Furthermore, lung lavage fluid from endotoxemic, ethanol-fed rats had more biologically active TGFbeta(1) protein than control-fed rats (p < 0.05), as reflected by anti-TGFbeta(1) antibody-inhibitable induction of permeability in rat alveolar epithelial monolayers in vitro. We conclude that chronic ethanol ingestion increases lung expression of TGFbeta(1,) which, during endotoxemia, is released and activated in the alveolar space in which it can disrupt the normally tight epithelial barrier. We speculate that this mechanism could contribute to the increased risk of acute respiratory distress syndrome in alcoholic patients.

Elevated plasma and lung endothelial selectin levels in patients with acute respiratory distress syndrome and a history of chronic alcohol abuse

OBJECTIVE

Activation of endothelial cells is a critical step in the pathogenesis of acute respiratory distress syndrome (ARDS). Soluble endothelial selectin (sE-selectin), an endothelial cell-specific molecule that mediates leukocyte-endothelial cell adhesion has never been measured in the bronchoalveolar lavage fluid of critically ill patients. Based on the effects of alcohol on endothelial cell and alveolar-capillary barrier function, we hypothesized that chronic alcohol exposure may be associated with increased sE-selectin in ARDS patients.

DESIGN

Prospective observational cohort study.

SETTING

Medical and surgical intensive care units; an inpatient alcohol detoxification unit within university-affiliated hospitals.

PATIENTS

A total of 20 ARDS patients (50% with chronic alcohol abuse); seven individuals with a history of chronic alcohol abuse.

INTERVENTION

Patients underwent bronchoalveolar lavage within 72 hrs of ARDS diagnosis. Individuals with a history of chronic alcohol abuse underwent bronchoalveolar lavage within 7 days of their last alcoholic beverage. A history of chronic alcohol abuse was determined by a Short Michigan Alcohol Screening Test score of > or =3 or a history of an alcohol-related diagnosis. sE-selectin was measured in plasma and bronchoalveolar lavage.

MEASUREMENTS AND MAIN RESULTS

Neither severity of illness nor at-risk diagnosis differed by alcohol history. sE-selectin levels in the plasma of ARDS patients who abused alcohol chronically were significantly elevated compared with nonalcoholic ARDS patients (181 ng/mL [56-328] vs. 32 ng/mL [14-55], p <.01). The bronchoalveolar lavage sE-selectin levels from the patients with ARDS and alcohol abuse were also significantly elevated compared with nonalcoholic ARDS patients (1.51 ng/mL [1.09-3.11] vs. 0.69 ng/mL [0.33-0.94], p <.002) and were higher than those measured in individuals with a history of chronic alcohol abuse but without ARDS (0.46 ng/mL [0.12-2.75], p =.15).

CONCLUSIONS

ARDS patients who chronically abuse alcohol have elevated concentrations of sE-selectin in both the plasma and epithelial lining fluid consistent with altered endothelial cell and alveolar-capillary barrier function.

Investigation of the course of proinflammatory and anti-inflammatory cytokines after burn sepsis

Cytokines have been considered as important participants in the post-burn pathophysiological process. The aim of this study was to investigate the course of a proinflammatory cytokine interleukin-8 (IL-8) and an anti-inflammatory cytokine IL-10 in burned patients and whether there was a correlation between mortality and serum levels of these cytokines. Thirty-six acutely burned patients, admitted to Ankara Numune hospital burn unit, entered into the study. A series of serum samples were collected, and serum levels of IL-8 and IL-10 were determined using enzyme-linked immunosorbent assay kit. According to definition utilised, 21 patients developed septic shock and nine of them died. There was no mortality among the 17 non-septic patients. In all 36 patients, there was an increase in serum IL-8 levels, and a peak level was detected shortly after burn injury. The peak IL-8 value of the non-survivors was greater when compared with that of the others. On admission, a significant difference in serum IL-8 values was found between survivors and those who died. In all patients, a peak level of IL-10 was detected between 5 and 9 days of injury. In non-septic survivors, this peak level was less when compared with that of the others. After this peak level, in all patients, serum IL-10 levels showed a decrease, but in non-survivors, a second peak level was detected. A greater understanding of the pathology of the burn sepsis allows rationale use and assessment of current therapies. The results obtained in this study provide useful information on the formulation approaches to this task. Also, IL-8 and IL-10 are prognostic factors in burn sepsis.

Polymorphism in the Surfactant Protein-B Gene, Gender, and the Risk of Direct Pulmonary Injury and ARDS

STUDY OBJECTIVE

Major risk factors for ARDS have been identified. However, only a minority of patients with such risks develops ARDS. It is likely that, given the same type and degree of insult, there are heritable determinants of susceptibility to ARDS. To investigate the possibility of variable genetic susceptibility to ARDS, we examined the association between ARDS and a polymorphism in intron 4 of the surfactant protein-B (SP-B) gene.

DESIGN

Nested case-control study conducted from September 1999 to March 2001.

SETTING

Four adult medical and surgical ICUs at a tertiary academic center.

PATIENTS

One hundred eighty-nine patients meeting study criteria for a defined risk factor for ARDS were enrolled and prospectively followed.

MEASUREMENTS AND RESULTS

Seventy-two patients (38%) developed ARDS. After stratification by gender and adjustment for potential confounders, there was a significantly increased odds for women with the variant SP-B gene to develop ARDS compared to women homozygous for the wild-type allele (odds ratio [OR], 4.5; 95% confidence interval [CI], 1.1 to 18.8; p = 0.03). Women with the variant SP-B polymorphism also had significantly increased odds of having a direct pulmonary injury such as aspiration or pneumonia as a risk factor for ARDS as opposed to an indirect pulmonary risk for ARDS (OR, 4.6; 95% CI, 1.1 to 19.9; p = 0.04). No such association with ARDS or direct pulmonary injury was found for men.

CONCLUSION

The variant polymorphism of the SP-B gene is associated with ARDS and with direct pulmonary injury in women, but not in men. Further study is needed to confirm the association between the variant SP-B gene, and gender, ARDS, and direct pulmonary injury.

Granulocyte/macrophage colony-stimulating factor treatment improves alveolar epithelial barrier function in alcoholic rat lung

Chronic alcohol abuse increases the risk of developing acute lung injury approximately threefold in septic patients, and ethanol ingestion for 6 wk in rats impairs alveolar epithelial barrier function both in vitro and in vivo. Granulocyte/macrophage colony-stimulating factor (GM-CSF) is a trophic factor for the alveolar epithelium, and a recent phase II clinical study suggests that GM-CSF therapy decreases sepsis-mediated lung injury. Therefore, we hypothesized that GM-CSF treatment could improve ethanol-mediated defects in the alveolar epithelium during acute stresses such as endotoxemia. In this study, we determined that recombinant rat GM-CSF improved lung liquid clearance (as reflected by lung tissue wet:dry ratios) in ethanol-fed rats anesthetized and then challenged with 2 ml of saline via a tracheostomy tube. Furthermore, GM-CSF treatment improved lung liquid clearance and decreased epithelial protein leak in both control-fed and ethanol-fed rats after 6 h of endotoxemia induced by Salmonella typhimurium lipopolysaccharide given intraperitoneally, but with the greater net effect seen in the ethanol-fed rats. Our previous studies indicate that chronic ethanol ingestion decreases lung liquid clearance by increasing intercellular permeability. Consistent with this, GM-CSF treatment in vitro decreased permeability of alveolar epithelial monolayers derived from both control-fed and ethanol-fed rats. As in the endotoxemia model in vivo, the effect of GM-CSF was most dramatic in the ethanol group. Together, these results indicate that GM-CSF treatment has previously unrecognized effects in promoting alveolar epithelial barrier integrity and that these salutary effects may be particularly relevant in the setting of chronic alcohol abuse.

Effect of age on the development of ARDS in trauma patients

STUDY OBJECTIVES

The purpose of this study was to determine the independent effect of age on the risk of developing ARDS in patients with trauma.

DESIGN

Prospective cohort study.

SETTING

Level I trauma center.

MEASUREMENTS AND RESULTS

A total of 4,020 consecutive trauma patients who were > 12 years of age were identified through the Harborview Medical Center Trauma Registry over a 3-year period. During this time, 484 of the trauma patients (12%) developed ARDS, as identified by the Harborview Medical Center ARDS Registry. Patients who developed ARDS were, on average, older (mean [+/- SD] age, 44.0 +/- 18.8 vs 40.2 +/- 20.0 years, respectively; p < 0.0001) and had higher injury severity scores (23.7 +/- 11.3 vs 18.0 +/- 10.3, respectively; p < 0.0001) than trauma patients who did not develop ARDS. The maximum unadjusted odds ratio for developing ARDS was 2.93 (95% confidence interval, 1.91 to 4.50) for the group 60 to 69 years of age compared to the group 13 to 19 years of age. Patients aged > or = 80 years had an equal risk of developing ARDS compared to those age 13 to 19 years.

CONCLUSIONS

Age demonstrated a complex relationship with risk for ARDS development. Older patients showed increasingly higher risks for ARDS development up to 60 to 69 years of age, when the risk for ARDS declined. We concluded that older patients are at significantly greater risk of developing ARDS when compared to younger patients, while the oldest patients may be at less risk.

Chronic ethanol ingestion increases expression of the angiotensin II type 2 (AT2) receptor and enhances tumor necrosis factor-alpha- and angiotensin II-induced cytotoxicity via AT2 signaling in rat alveolar epithelial cells

BACKGROUND

Alcohol abuse increases the risk of acute lung injury in critically ill patients. We have shown that alveolar epithelial cell (AEC) apoptosis in response to inflammatory mediators, including tumor necrosis factor-alpha (TNF-alpha), parallels endotoxin-mediated acute lung injury in ethanol-fed rats. Although angiotensin II mediates TNF-alpha-induced apoptosis of AECs in vitro, its role in ethanol-mediated susceptibility to AEC apoptosis is unknown.

METHODS

Adult male rats were fed the Lieber-DeCarli diet for 6 weeks. AECs were isolated, and TNF-alpha- and angiotensin II-induced cytotoxicity (by terminal transferase-mediated dUTP nick end labeling staining) was determined with or without the addition of the angiotensin-converting enzyme inhibitor (lisinopril) or a selective blocker of the angiotensin II type 1 receptor (AT(1)) or type 2 receptor (AT(2)). Finally, the relative expression of the AT(1) and AT(2) receptors in AECs was determined by Western blot analysis.

RESULTS

TNF-alpha-induced cytotoxicity, but not angiotensin II-induced cytotoxicity, was prevented by lisinopril, indicating that de novo angiotensin II synthesis is required for TNF-alpha-induced apoptosis in these cells. Both TNF-alpha- and angiotensin II-induced cytotoxicity in AECs from control-fed and ethanol-fed rats were inhibited by the selective AT(2) blocker, PD123319, but not by the selective AT(1) blocker, losartan. In parallel, ethanol ingestion doubled AT(2) expression in AECs (by Western blot) but had no significant effect on AT(1) receptor expression.

CONCLUSIONS

Chronic ethanol ingestion increases AT(2) expression in the alveolar epithelium and enhances TNF-alpha- and angiotensin II-induced cytotoxicity, both of which act via AT(2). Together, these findings suggest that selective AT(2) receptor inhibition could limit the development of acute lung injury in alcoholic patients.

Chronic alcohol abuse, acute respiratory distress syndrome, and multiple organ dysfunction

OBJECTIVE

To review the effects of chronic alcohol abuse on the incidence, severity, and pathogenesis of acute respiratory distress syndrome (ARDS) and multiple organ dysfunction.

DATA SOURCES

A summary of published medical literature from MEDLINE search files and other reviews published concerning chronic alcohol abuse and critical illness.

DATA SUMMARY

A history of chronic alcohol abuse is associated with an increased incidence and severity of ARDS in critically ill patients. In two separate epidemiologic studies, involving 571 intensive care patients, chronic alcohol abuse was a significant comorbid variable that increased the incidence of ARDS by nearly three-fold and was associated with more severe nonpulmonary organ dysfunction. In addition, nearly 50% of all ARDS patients had a significant history of chronic alcohol abuse, making the association between chronic alcohol abuse and ARDS a common scenario in the intensive care unit. By using animal models of chronic ethanol ingestion, researchers have identified alcohol-mediated alterations in epithelial and endothelial cell function, surfactant synthesis and secretion, alveolar-capillary barrier function, and lung matrix content and composition. More importantly, similar changes have been reported in humans with a history of chronic alcohol abuse. Individuals with a history of chronic alcohol abuse have decreased concentrations of glutathione in the epithelial lining fluid of the lung, which do not significantly increase after 1 wk of abstinence from alcohol. The total protein concentration in the epithelial lining fluid also is increased in these individuals with a history of chronic alcohol abuse compared with healthy controls, suggesting alterations in alveolar-capillary barrier function.

CONCLUSIONS

Chronic alcohol abuse is associated with an increased incidence of ARDS and the severity of multiple organ dysfunction. This research has implications in understanding the diagnosis of, and prognosis for, critically ill patients who are at risk of developing ARDS. It also may lead to the development of novel therapies for those patients at greatest risk of acute lung injury as a consequence of chronic alcohol abuse.

Epidemiology of acute lung injury

OBJECTIVE

To review the epidemiology of acute lung injury (ALI) with particular emphasis on its effect on public health.

DATA SOURCES

Published studies on the definitions, incidence, and outcomes of ALI.

DATA SUMMARY

ALI is a syndrome of acute hypoxemic respiratory failure that is not primarily cardiac in origin. The diagnostic criteria for the syndrome have not been well studied for their reliability or validity. The lack of a gold standard for the diagnosis of ALI is a challenge to clinical investigation. Recent data on the incidence of ALI (20-50 cases/105 person-years) indicate that it is more common than previous estimates for the incidence of acute respiratory distress syndrome (3-8 cases/105 person-years). There is conflicting evidence as to whether the mortality rate in the broader patient population with ALI is different from the mortality rate in acute respiratory distress syndrome. Mortality attributable to and associated with ALI in the United States is comparable to HIV infection, breast cancer, and asthma. Morbidity from impaired cognitive function, functional status, and psychiatric complications has been reported in survivors of ALI.

CONCLUSIONS

Recent studies of the epidemiology of ALI have reported higher incidence rates for this syndrome than previously described. The mortality and morbidity rates associated with ALI are considerable, with significant impact on public health.