Clinical studies have demonstrated that chronic alcohol abuse is an independent result variable in acute lung injury.

Clinical studies have demonstrated that chronic alcohol abuse is an independent result variable in acute lung injury. The Emory Center for the consideration of Acute Lung Injury is determining the mechanisms by the agency of which ethanol increases susceptibility to acute lung injury. We discloseed a rat model of chronic ethanol ingestion and demonstrated that ethanol predisposes rats to edematous lung injury elicited by the agency of endotoxemia or sepsis. Chronic ethanol ingestion in rats l to decreased horizontals of glutathione, an important antioxidant in the lung and this flaw was associated with alterations in epithelial small room permeability, decreased alveolar liquid clearance, decreased confined apartment viability, and decreased surfactant production. Chronic ethanol ingestion also l to the activation of lung tissue remodeling as demonstrated by dint of the increased expression of profibrotic bourgeoning factors, matrix components, and metalloproteases. In cultur fibroblasts, the induction of the matrix glycoprotein fibronectin through ethanol was mediated via nicotinic acetylcholine receptor-dependent signal transduction. We speculate that these alterations give the host susceptible to acute lung injury by way of diminishing the protective mechanisms of the lung and promoting exaggerated inflammatory and tissue repair replications elicited against injurious agents.

key-note words: acute lung injury; ethanol; fibronectin; glutathione; tissue remodeling

Abbreviations: [alpha]-BGT = [alpha]-bungarotoxin; bp = base pair; cAMP = cyclic adenosine monophosphate; CRE = cyclic adenosine monophosphate responsive element; CREB = cyclic adenosine monophosphate responsive proper state binding protein; nAChR = nicotinic acetylcholine receptor

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ARDS is an important and universal disease process that afflicts approximately 75000 to 150000 individuals by year in the United States. (1) The greatest in quantity common at-risk diagnoses associated with the increase of ARDS are sepsis, trauma, and the aspiration of gastric satisfys The mechanisms that lead to the exhibition of this syndrome in about patients and not others are unknown, still a recent discovery points to alcohol abuse as an important predisposing factor. Herein, we describe our findings linking chronic alcohol abuse with alterations in lung mode of building and function that render the army susceptible to acute lung injury.

ETHANOL AND ACUTE LUNG INJURY

The association between alcohol abuse and ARDS was first identified by dint of the work of Moss and colleagues, (2) who demonstrated that chronic alcohol abuse in humans independently increases the incidence of ARDS in at-risk patients, and is associated with increased mortality related to multiorgan failure. In their cogitation (2) they evaluated the hospital courses of 351 consecutive patients with single in kind of seven diagnoses associated with the progress to maturity of ARDS. Thirty-four percent of the patients (121 of 351 patients) were defined as chronic alcoholics. Using a strict definition of ARDS, 43% of the alcoholics acquired ARDS, as oppos to 22% of the nonalcoholics (p < 0001; relative risk, 198; 95% confidence interval, 132 to 285) Furthermore, in the patients who acquired ARDS (n = 102) the in-hospital mortality rate was higher in chronic alcoholics (65%) than in nonalcoholics (36%) [p = 0003]

This observation was compelling because it provided an important [i]clavis[/i] as to why some patients are at increased risk of acquiring ARDS. We reasoned that if we could identify the precise mechanisms on which alcohol abuse predisposes to acute lung injury, we could learn more about the pathophysiology of the syndrome and design treatment strategies capable of limiting the progressive growth and/or severity of ARDS in this important subset of patients. To this extreme point we first developed a rat pattern of ethanol-mediated susceptibility to acute lung injury. As seen in humans, chronic ethanol ingestion (> 3 weeks) increased endotoxin-mediated acute edematous injury in rat lung isolated and perfused ex vivo. (34) In addition, ethanol increased sepsis-mediated lung dysfunction in vivo (unpublished data).

These novel observations linking alcohol with increased susceptibility to clinical and experimental lung injury are important for sum of two units reasons. First, they strengthen the idea that alcohol has direct tenors on the lung. Second, they provide a unique opportunity to explore the factors and mechanisms involved in the evolution of acute lung injury. We nearest focused our efforts on identifying the discrete mechanisms by the agency of which ethanol ingestion renders the lung susceptible to acute edematous injury. This work implicated oxidative stres and tissue remodeling as elucidation determinants of this process and is summarized below.

character OF GLUTATHIONE IN ETHANOL-MEDIATED SUSCEPTIBILITY TO ACUTE LUNG INJURY

Previous studies of alcohol-mediated liver disease provided firm evidence that depletion of the antioxidant glutathione is a critical stair in the pathogenesis of that disorder. chiefly importantly, they demonstrated that glutathione replacement with treatments that restore and/or maintain mitochondrial glutathione flats prevents ethanol-mediated hepatotoxicity. (5,6) However, there had not been any parallel investigations in the lung because a link between alcohol abuse and ARDS had not been identified previously.

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