Antiviral Approaches against Influenza Virus.

Preventing and controlling influenza virus infection remains a global public health challenge, as it causes seasonal epidemics to unexpected pandemics. These infections are responsible for high morbidity, mortality, and substantial economic impact. Vaccines are the prophylaxis mainstay in the fight against influenza. However, vaccination fails to confer complete protection due to inadequate vaccination coverages, vaccine shortages, and mismatches with circulating strains. Antivirals represent an important prophylactic and therapeutic measure to reduce influenza-associated morbidity and mortality, particularly in high-risk populations. Here, we review current FDA-approved influenza antivirals with their mechanisms of action, and different viral- and host-directed influenza antiviral approaches, including immunomodulatory interventions in clinical development. Furthermore, we also illustrate the potential utility of machine learning in developing next-generation antivirals against influenza.

Human Innate Lymphoid Cells in Influenza Infection and Vaccination.

Influenza is a highly contagious respiratory virus that causes mild to severe respiratory illness, as well as death, and remains a serious threat to human health. Annual vaccination is the most cost-effective way to control influenza; however, the vaccine does not provide protection against emerging strains with epidemic and pandemic potential. Several antivirals have been developed to treat influenza but there is a rapid emergence of antiviral resistant strains. Therefore, there is an urgent need to understand the virus and its interactions with the host immune system so that novel strategies can be developed for prophylactic and therapeutic interventions. Innate lymphoid cells (ILCs), a family of immune cells present in the peripheral circulation and in mucosal tissues, play an important role in regulation of tissue homeostasis, inflammation, and immunity. This review examines the current understanding and therapeutic potential of ILCs during influenza virus infection in humans.

Directed vaccination against pneumococcal disease.

Immunization strategies against commensal bacterial pathogens have long focused on eradicating asymptomatic carriage as well as disease, resulting in changes in the colonizing microflora with unknown future consequences. Additionally, current vaccines are not easily adaptable to sequence diversity and immune evasion. Here, we present a "smart" vaccine that leverages our current understanding of disease transition from bacterial carriage to infection with the pneumococcus serving as a model organism. Using conserved surface proteins highly expressed during virulent transition, the vaccine mounts an immune response specifically against disease-causing bacterial populations without affecting carriage. Aided by a delivery technology capable of multivalent surface display, which can be adapted easily to a changing clinical picture, results include complete protection against the development of pneumonia and sepsis during animal challenge experiments with multiple, highly variable, and clinically relevant pneumococcal isolates. The approach thus offers a unique and dynamic treatment option readily adaptable to other commensal pathogens.

Volatile Anesthetics and Immunity.

Historically, volatile anesthetics have demonstrated interesting interactions with both the innate and adaptive immune systems. This review organizes these interactions into four phases: recognition, recruitment, response, and resolution. These phases represent a range of proinflammatory, inflammatory, and innate and adaptive immune regulatory responses. The interaction between volatile anesthetics and the immune system is discussed in the context of pathogenesis of infectious disease.

Halothane modulates the type i interferon response to influenza and minimizes the risk of secondary bacterial pneumonia through maintenance of neutrophil recruitment in an animal model.

BACKGROUND: To minimize the risk of pneumonia, many anesthesiologists delay anesthesia-requiring procedures when patients exhibit signs of viral upper respiratory tract infection. Postinfluenza secondary bacterial pneumonias (SBPs) are a major cause of morbidity and mortality. An increased host susceptibility to SBP postinfluenza has been attributed to physical damage to the pulmonary epithelium, but flu-induced effects on the immune system are being shown to also play an important role. The authors demonstrate that halothane mitigates the risk of SBP postflu through modulation of the effects of type I interferon (IFN). METHODS: Mice (n = 6 to 15) were exposed to halothane or ketamine and treated with influenza and Streptococcus pneumoniae. Bronchoalveolar lavage and lung homogenate were procured for the measurement of inflammatory cells, cytokines, chemokines, albumin, myeloperoxidase, and bacterial load. RESULTS: Halothane exposure resulted in decreased bacterial burden (7.9 ± 3.9 × 10 vs. 3.4 ± 1.6 × 10 colony-forming units, P < 0.01), clinical score (0.6 ± 0.2 vs. 2.3 ± 0.2, P < 0.0001), and lung injury (as measured by bronchoalveolar lavage albumin, 1.5 ± 0.7 vs. 6.8 ± 1.6 mg/ml, P < 0.01) in CD-1 mice infected with flu for 7 days and challenged with S. pneumoniae on day 6 postflu. IFN receptor A1 knockout mice similarly infected with flu and S. pneumoniae, but not exposed to halothane, demonstrated a reduction of lung bacterial burden equivalent to that achieved in halothane-exposed wild-type mice. CONCLUSION: These findings indicate that the use of halogenated volatile anesthetics modulates the type I IFN response to influenza and enhance postinfection antibacterial immunity.

NADPH oxidase and Nrf2 regulate gastric aspiration-induced inflammation and acute lung injury.

Recruitment of neutrophils and release of reactive oxygen species are considered to be major pathogenic components driving acute lung injury (ALI). However, NADPH oxidase, the major source of reactive oxygen species in activated phagocytes, can paradoxically limit inflammation and injury. We hypothesized that NADPH oxidase protects against ALI by limiting neutrophilic inflammation and activating Nrf2, a transcriptional factor that induces antioxidative and cytoprotective pathways. Our objective was to delineate the roles of NADPH oxidase and Nrf2 in modulating acute lung inflammation and injury in clinically relevant models of acute gastric aspiration injury, a major cause of ALI. Acid aspiration caused increased ALI (as assessed by bronchoalveolar lavage fluid albumin concentration) in both NADPH oxidase-deficient mice and Nrf2(-/-) mice compared with wild-type mice. NADPH oxidase reduced airway neutrophil accumulation, but Nrf2 decreased ALI without affecting neutrophil recovery. Acid injury resulted in a 120-fold increase in mitochondrial DNA, a proinflammatory and injurious product of cellular necrosis, in cell-free bronchoalveolar lavage fluid. Pharmacologic activation of Nrf2 by the triterpenoid 1-[2-cyano-3-,12-dioxooleana-1,9 (11)-dien-28-oyl]imidazole limited aspiration-induced ALI in wild-type mice and reduced endothelial cell injury caused by mitochondrial extract-primed human neutrophils, leading to the conclusion that NADPH oxidase and Nrf2 have coordinated, but distinct, functions in modulating inflammation and injury. These results also point to Nrf2 as a therapeutic target to limit ALI by attenuating neutrophil-induced cellular injury.

Monocyte- and macrophage-targeted NADPH oxidase mediates antifungal host defense and regulation of acute inflammation in mice.

Chronic granulomatous disease, an inherited disorder of the NADPH oxidase in which phagocytes are defective in the generation of superoxide anion and downstream reactive oxidant species, is characterized by severe bacterial and fungal infections and excessive inflammation. Although NADPH oxidase isoforms exist in several lineages, reactive oxidant generation is greatest in neutrophils, where NADPH oxidase has been deemed vital for pathogen killing. In contrast, the function and importance of NADPH oxidase in macrophages are less clear. Therefore, we evaluated susceptibility to pulmonary aspergillosis in globally NADPH oxidase-deficient mice versus transgenic mice with monocyte/macrophage-targeted NADPH oxidase activity. We found that the lethal inoculum was >100-fold greater in transgenic versus globally NADPH oxidase-deficient mice. Consistent with these in vivo results, NADPH oxidase in mouse alveolar macrophages limited germination of phagocytosed Aspergillus fumigatus spores. Finally, globally NADPH oxidase-deficient mice developed exuberant neutrophilic lung inflammation and proinflammatory cytokine responses to zymosan, a fungal cell wall-derived product composed principally of particulate ß-glucans, whereas inflammation in transgenic and wild-type mice was mild and transient. Taken together, our studies identify a central role for monocyte/macrophage NADPH oxidase in controlling fungal infection and in limiting acute lung inflammation.

Dietary advanced glycation end-products, its pulmonary receptor, and high mobility group box 1 in aspiration lung injury.

BACKGROUND: Gastric aspiration is a significant cause of acute lung injury and acute respiratory distress syndrome. Environmental risk factors, such as a diet high in proinflammatory advanced glycation end-products (AGEs), may render some patients more susceptible to lung injury after aspiration. We hypothesized that high dietary AGEs increase its pulmonary receptor, RAGE, producing an amplified pulmonary inflammatory response in the presence of high mobility group box 1 (HMGB1), a RAGE ligand and an endogenous signal of epithelial cell injury after aspiration. MATERIALS AND METHODS: CD-1 mice were fed either a low AGE or high AGE diet for 4 wk. After aspiration injury with acidified small gastric particles, bronchoalveolar lavage and whole-lung tissue samples were collected at 5 min, 1 h, 5 h, and 24 h after injury. RAGE, soluble RAGE (sRAGE), HMGB1, cytokine and chemokine concentrations, albumin levels, neutrophil influx, and lung myeloperoxidase activity were measured. RESULTS: We observed that high AGE-fed mice exhibited greater pulmonary RAGE levels before aspiration and increased bronchoalveolar lavage sRAGE levels after aspiration compared with low AGE-fed mice. Lavage HMGB1 levels rose immediately after aspiration, peaking at 1 h, and strongly correlated with sRAGE levels in both dietary groups. High AGE-fed mice demonstrated higher cytokine and chemokine levels with increased pulmonary myeloperoxidase activity over 24 h versus low AGE-fed mice. CONCLUSIONS: This study indicates that high dietary AGEs can increase pulmonary RAGE, augmenting the inflammatory response to aspiration in the presence of endogenous damage signals such as HMGB1.

Gold nanorod delivery of an ssRNA immune activator inhibits pandemic H1N1 influenza viral replication.

The emergence of the pandemic 2009 H1N1 influenza virus has become a world-wide health concern. As drug resistance appears, a new generation of therapeutic strategies will be required. Here, we introduce a nanotechnology approach for the therapy of pan-demic and seasonal influenza virus infections. This approach uses gold nanorods (GNRs) to deliver an innate immune activator, pro-ducing a localized therapeutic response. We demonstrated the utility of a biocompatible gold nanorod, GNR-5'PPP-ssRNA nanoplex, as an antiviral strategy against type A influenza virus. In human respiratory bronchial epithelial cells, this nanoplex activated the retinoic acid-inducible gene I (RIG-I) pathogen recognition pathway, resulting in increased expression of IFN-beta and other IFN-stimulated genes (ISGs) (e.g., PKR, MDA5, IRF1, IRF7, and MX1). This increase in type I IFN and ISGs resulted in a decrease in the replication of H1N1 influenza viruses. These findings suggest that further evaluation of biocompatible nanoplexes as unique antivirals for treatment of seasonal and pandemic influenza viruses is warranted.

Sevoflurane-mediated modulation of oxidative myocardial injury.

Introduction: Volatile anesthetics offer protection when administered throughout an ischemic injury. We examined how volatile anesthetics modulate the cardiac myocytic injury associated with hydrogen peroxide. Methods: Forty-eight Long-Evans rats were divided into four groups depending on the treatment: none (CONT), Glibenclamide (GLB); Sevoflurane (SEV); or GLB+SEV. Each group was further divided into two, one of which was exposed to hydrogen peroxide (H2O2). Oral GLB was administered 48 hours before myocardial isolation. All rats were anesthetized by intraperitoneal injection of Ketamine, and the hearts were harvested after heparinization. Cardiomyocytes were isolated using a combination of mechanical mincing and enzymatic digestion. After isolation, the aliquots of cells were exposed to H2O2 and FeSO4 for 30 minutes. The cell suspensions were then bubbled for 10 minutes with 100% oxygen and 1.5% SEV if appropriate. Apoptosis was detected by fluorescein-bound annexin-V (ANX-V), necrosis by propidium iodide, and ELISA assessed caspase-3 activity in all groups. Results: There was an increase in apoptosis, necrosis, and caspase-3 activity in the cells following exposure to hydrogen peroxide. SEV reduced the rate of cell necrosis and apoptosis. Pretreatment with GLB did not alter the effects of SEV. Similarly, caspase-3 activity did not change with GLB, although SEV administration reduced this enzymatic activity in response to hydrogen peroxide. Conclusion: In this oxidant injury model, we demonstrated that incubating isolated cardiomyocytes with SEV profoundly diminished H2O2-induced apoptotic and necrotic cells compared to their CONTs. These results support the hypothesis that KATP channels are not the sole mediators associated with anesthetic preconditioning.

Role of macrophage chemoattractant protein-1 in acute inflammation after lung contusion.

Lung contusion (LC), commonly observed in patients with thoracic trauma is a leading risk factor for development of acute lung injury/acute respiratory distress syndrome. Previously, we have shown that CC chemokine ligand (CCL)-2, a monotactic chemokine abundant in the lungs, is significantly elevated in LC. This study investigated the nature of protection afforded by CCL-2 in acute lung injury/acute respiratory distress syndrome during LC, using rats and CC chemokine receptor (CCR) 2 knockout (CCR2(-/-)) mice. Rats injected with a polyclonal antibody to CCL-2 showed higher levels of albumin and IL-6 in the bronchoalveolar lavage and myeloperoxidase in the lung tissue after LC. Closed-chest bilateral LC demonstrated CCL-2 localization in alveolar macrophages (AMs) and epithelial cells. Subsequent experiments performed using a murine model of LC showed that the extent of injury, assessed by pulmonary compliance and albumin levels in the bronchoalveolar lavage, was higher in the CCR2(-/-) mice when compared with the wild-type (WT) mice. We also found increased release of IL-1ß, IL-6, macrophage inflammatory protein-1, and keratinocyte chemoattractant, lower recruitment of AMs, and higher neutrophil infiltration and phagocytic activity in CCR2(-/-) mice at 24 hours. However, impaired phagocytic activity was observed at 48 hours compared with the WT. Production of CCL-2 and macrophage chemoattractant protein-5 was increased in the absence of CCR2, thus suggesting a negative feedback mechanism of regulation. Isolated AMs in the CCR2(-/-) mice showed a predominant M1 phenotype compared with the predominant M2 phenotype in WT mice. Taken together, the above results show that CCL-2 is functionally important in the down-modulation of injury and inflammation in LC.

Diagnostic use of serum procalcitonin levels in pulmonary aspiration syndromes.

OBJECTIVE: To assess the predictive accuracy of serum procalcitonin in distinguishing bacterial aspiration pneumonia from aspiration pneumonitis. DESIGN: Prospective observational study. SETTING: Intensive care unit of a university-affiliated hospital. PATIENTS: Sixty-five consecutive patients admitted with pulmonary aspiration and seven control subjects intubated for airway protection. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Quantitative cultures from bronchoalveolar lavage fluid were conducted on all participants at the time of admission. Serial serum procalcitonin levels were measured on day 1 and day 3 using the procalcitonin enzyme-linked fluorescent assay. There were no differences in the median serum concentrations of procalcitonin between patients with positive bronchoalveolar lavage cultures (n = 32) and patients with negative bronchoalveolar lavage cultures (n = 33) on either day 1 or day 3 postadmission. The areas under the receiver operator characteristic curves were 0.59 (95% confidence interval, 0.47-0.72) and 0.63 (95% confidence interval, 0.5-0.75), respectively (p = .74). However, duration of mechanical ventilation and antibiotic therapy were shorter in those who had a decrease in their procalcitonin levels on day 3 from baseline compared with those who did not (6.7 ± 7.1 days and 11.1 ± 13.5 days, p = .03; and 8.2 ± 2.6 days vs. 12.8 ± 4.6 days; p < .001, respectively). Hospital mortality was associated with radiographic multilobar disease (adjusted odds ratio, 1.14; 95% confidence interval, 1.01-1.31; p = .04) and increasing procalcitonin levels (adjusted odds ratio, 5.63; 95% confidence interval, 1.56-20.29; p = .008). CONCLUSION: Serum procalcitonin levels had poor diagnostic value in separating bacterial aspiration pneumonia from aspiration pneumonitis based on quantitative bronchoalveolar lavage culture. However, serial measurements of serum procalcitonin may be helpful in predicting survival from pulmonary aspiration.

Aspiration-induced lung injury.

OBJECTIVE: Aspiration of oropharyngeal or gastric contents into the lower respiratory tract is a common event in critically ill patients and can lead to pneumonia or pneumonitis. Aspiration pneumonia is the leading cause of pneumonia in the intensive care unit and is one of the leading risk factors for acute lung injury and acute respiratory distress syndromes. Despite its frequency, it remains largely a disease of exclusion characterized by ill-defined infiltrates on the chest radiograph and hypoxia. An accurate ability to diagnose aspiration is paramount because different modalities of therapy, if applied early and selectively, could change the course of the disease. This article reviews definitions, diagnosis, epidemiology, pathophysiology, including animal models of aspiration-induced lung injury, and evidence-based clinical management. Additionally, a review of current and potential biomarkers that have been tested clinically in humans is provided. DATA SOURCES: Data were obtained from a PubMed search of the medical literature. PubMed "related articles" search strategies were used. SUMMARY AND CONCLUSIONS: Aspiration in the intensive care unit is a clinically relevant problem requiring expertise and awareness. A definitive diagnosis of aspiration pneumonitis or pneumonia is challenging to make. Advances in specific biomarker profiles and prediction models may enhance the diagnosis and prognosis of clinical aspiration syndromes. Evidence-based management is supportive, including mechanical ventilation, bronchoscopy for particulate aspiration, consideration of empiric antibiotics for pneumonia treatment, and lower respiratory tract sampling to define pathogenic bacteria that are causative.

Doxorubicin-conjugated quantum dots to target alveolar macrophages and inflammation.

The ability to provide targeted therapeutic delivery in the lung would be a major advancement in pharmacological treatments for many pulmonary diseases. Critical issues for such successful delivery would require the ability to target specific cell types, minimize toxicity (e.g., inflammatory response), and deliver therapeutic levels of drugs. We report here on the ability of nanoconjugates of CdSe/CdS/ZnS quantum dots (QDs) and doxorubicin (Dox) to target alveolar macrophages (aMØs), cells that play a critical role in the pathogenesis of inflammatory lung injuries. Confocal imaging showed the release of Dox from the QD-Dox nanoconjugate, as was evident by its accumulation in the cell nucleus and induction of apoptosis, implying that the drug retains its bioactivity after coupling to the nanoparticle. Inflammatory injury parameters (albumin leakage, proinflammatory cytokines, and neutrophil infiltration) were recorded after in vivo administration of QD-Dox and Dox, observing no significant effect after QD-Dox treatment compared with Dox. These results demonstrate that nanoparticle platforms can provide targeted macrophage-selective therapy for the treatment of pulmonary disease. FROM THE CLINICAL EDITOR: Pulmonary inflammatory diseases still often remain challenging to treat, despite decades of advances and several available agents. In this study, a quantum dot-based alveolar delivery system is presented, targeting macrophages with doxorubicin.

A Dual-Functioning 5'-PPP-NS1shRNA that Activates a RIG-I Antiviral Pathway and Suppresses Influenza NS1.

Retinoic acid-inducible gene-I (RIG-I) is a cytosolic pathogen sensor that is crucial against a number of viral infections. Many viruses have evolved to inhibit pathogen sensors to suppress host innate immune responses. In the case of influenza, nonstructural protein 1 (NS1) suppresses RIG-I function, leading to viral replication, morbidity, and mortality. We show that silencing NS1 with in-vitro-transcribed 5'-triphosphate containing NS1 short hairpin RNA (shRNA) (5'-PPP-NS1shRNA), designed using the conserved region of a number of influenza viruses, not only prevented NS1 expression but also induced RIG-I activation and type I interferon (IFN) expression, resulting in an antiviral state leading to inhibition of influenza virus replication in vitro. In addition, administration of 5'-PPP-NS1shRNA in prophylactic and therapeutic settings resulted in significant inhibition of viral replication following viral challenge in vivo in mice with corresponding increases of RIG-I, IFN-ß, and IFN-λ, as well as a decrease in NS1 expression.

Tissue inhibitor of metalloproteinase-1 modulates allergic lung inflammation in murine asthma.

Matrix metalloproteinases (MMPs) modulate development, inflammation, and repair in lungs. Tissue inhibitors of MMPs (TIMPs) interact with MMPs, controlling the intensity and nature of the response to injury. Absence of MMP-9, -2, and -8 activities is associated with altered lung inflammation during allergic sensitization. To test the hypothesis that the absence of TIMP-1 enhances allergic lung inflammation, airway hyperreactivity (AHR), and lung remodeling in asthma, we studied TIMP-1 null (TIMP-1 KO) mice and their WT controls using an ovalbumin (OVA) asthma model. TIMP-1 KO mice, compared to WT controls, developed an asthma phenotype characterized by AHR, pronounced cellular lung infiltrates, greater reduction in lung compliance, enhanced Th2 cytokine mRNA and protein expression, and altered collagen lung content associated with enhanced MMP-9 activity. Our findings support the hypothesis that TIMP-1 plays a protective role by preventing AHR and modulating inflammation, remodeling, and cytokine expression in an animal model of asthma.

Superimposed gastric aspiration increases the severity of inflammation and permeability injury in a rat model of lung contusion.

INTRODUCTION: Lung contusion (LC) from blunt thoracic trauma is a clinically-prevalent condition that can progress to acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Patients with LC are at risk for gastric aspiration at the time of trauma, but the combined insults have not been well-studied in animal models. This study tests the hypothesis that concurrent gastric aspiration (combined acid and small gastric particles, CASP) at the time of trauma significantly increases permeability injury and inflammation compared with LC alone, and also modifies the inflammatory response to include distinct features compared with the aspiration component of injury. MATERIALS AND METHODS: Four groups of adult male Long-Evans rats were studied (LC, CASP, LC+CASP, uninjured controls). LC was induced in anesthetized rats at a fixed impact energy of 2.0 J, and CASP (1.2 mL/kg body weight, 40 mg particles/mL, pH=1.25) was instilled through an endotracheal tube. Lung injury and inflammation were assessed by arterial blood gases and levels of albumin, cells, and cytokines/chemokines in bronchoalveolar lavage (BAL) at 5 and 24 h. RESULTS: Rats with LC+CASP had lower mean PaO(2)/FiO(2) ratios compared with LC alone at 24 h, and higher BAL albumin concentrations compared with either LC or CASP alone. Rats with LC+CASP versus LC had more severe inflammation based on higher levels of PMN in BAL at 5 h, increased whole lung myeloperoxidase (MPO) activity at 5 and 24 h, and increased levels of inflammatory mediators in BAL (TNFalpha, IL-1beta, and MCP-1 at 5 and 24 h; IL-10, MIP-2, and CINC-1 at 5 h). Rats with LC+CASP also had distinct aspects of inflammation compared with CASP alone, i.e., significantly higher levels of IL-10 (5 and 24 h), IL-1beta (24 h), CINC-1 (24 h), and MCP-1 (24 h), and significantly lower levels of MPO (5 h), MIP-2 (5 h), and CINC-1 (5 h). CONCLUSIONS: Concurrent gastric aspiration can exacerbate permeability lung injury and inflammation associated with LC, and also generates a modified inflammatory response compared with aspiration alone. Unwitnessed gastric aspiration has the potential to contribute to more severe forms of LC injury associated with progression to ALI/ARDS and pneumonia in patients with thoracic trauma.

Predictive modeling and inflammatory biomarkers in rats with lung contusion and gastric aspiration.

BACKGROUND: This study uses statistical predictive modeling and hierarchical cluster analyses to examine inflammatory mediators and cells in bronchoalveolar lavage (BAL) as putative biomarkers in rats with blunt trauma lung contusion (LC), gastric aspiration (combined acid and small gastric food particles, CASP), or a combination of the two. METHODS: Specific parameters assessed in the innate pulmonary inflammatory response were leukocytes, macrophages, and polymorphonuclear neutrophils (PMNs) in BAL; whole lung myeloperoxidase activity; and a series of cytokines or chemokines present in BAL at 5 or 24 hours after injury: tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, interferon-gamma, IL-10, macrophage inflammatory protein-2, cytokine-induced neutrophil chemoattractant-1, and monocyte chemoattractant protein-1. RESULTS: Rats with LC, CASP, LC + CASP all had severe lung injury compared with uninjured controls based on decreased arterial oxygenation or increased BAL albumin at 5 or 24 hours postinsult. However, the injury groups had distinct overall patterns of inflammation that allowed them to be discriminated accurately by hierarchical cluster analysis (29 of 30 and 35 of 37 rats were correctly classified in hierarchical clusters at 5 and 24 hours, respectively). Moreover, predictive analyses based on an extension of standard receiver-operator characteristic methodology discriminated individual animals and groups with similar high accuracy based on a maximum of two inflammatory parameters per group (29 of 30 and 36 of 37 rats were correctly classified at 5 hours and 24 hours, respectively). CONCLUSIONS: These results support the possibility that inflammatory biomarker profiles could be developed in the future to improve the diagnosis and management of trauma patients with unwitnessed (occult) gastric aspiration who have an increased risk of clinical acute lung injury or the acute respiratory distress syndrome.

Pharmacotherapy of acute lung injury and acute respiratory distress syndrome.

Acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) are characterized by rapid-onset respiratory failure following a variety of direct and indirect insults to the parenchyma or vasculature of the lungs. Mortality from ALI/ARDS is substantial, and current therapy primarily emphasizes mechanical ventilation and judicial fluid management plus standard treatment of the initiating insult and any known underlying disease. Current pharmacotherapy for ALI/ARDS is not optimal, and there is a significant need for more effective medicinal chemical agents for use in these severe and lethal lung injury syndromes. To facilitate future chemical-based drug discovery research on new agent development, this paper reviews present pharmacotherapy for ALI/ARDS in the context of biological and biochemical drug activities. The complex lung injury pathophysiology of ALI/ARDS offers an array of possible targets for drug therapy, including inflammation, cell and tissue injury, vascular dysfunction, surfactant dysfunction, and oxidant injury. Added targets for pharmacotherapy outside the lungs may also be present, since multiorgan or systemic pathology is common in ALI/ARDS. The biological and physiological complexity of ALI/ARDS requires the consideration of combined-agent treatments in addition to single-agent therapies. A number of pharmacologic agents have been studied individually in ALI/ARDS, with limited or minimal success in improving survival. However, many of these agents have complementary biological/biochemical activities with the potential for synergy or additivity in combination therapy as discussed in this article.

Antinociception mediated by alpha(2)-adrenergic activation involves increasing tumor necrosis factor alpha (TNFalpha) expression and restoring TNFalpha and alpha(2)-adrenergic inhibition of norepinephrine release.

The central component that establishes chronic pain from peripheral nerve injury is associated with increased tumor necrosis factor-alpha (TNFalpha) production in the brain. This study examined TNFalpha and its reciprocally permissive role with alpha(2)-adrenergic activation during peak and progressive decline of thermal hyperalgesia in sciatic nerve chronic constriction injury (CCI). Accumulation of TNFalpha mRNA (in situ hybridization) increases in the hippocampus and locus coeruleus during the onset of neuropathic pain and persists as hyperalgesia abates. Activation of alpha(2)-adrenergic receptors in control rats decreases TNFalpha mRNA accumulation in these brain regions. In contrast, during hyperalgesia, alpha(2)-adrenergic activation enhances TNFalpha mRNA accumulation. Whether this enhanced TNFalpha production is associated with changes in the regulation of norepinephrine (NE) release was tested. Hippocampal slices were electrically depolarized to evaluate alpha(2)-adrenergic and TNFalpha regulation of NE release. While inhibition of NE release by TNFalpha is maximal during peak hyperalgesia, it subsequently transforms to facilitate NE release. In addition, alpha(2)-adrenergic receptor activation with clonidine (0.2mg/kg, i.p.) in CCI rats experiencing hyperalgesia restores TNFalpha and alpha(2)-adrenergic inhibition of NE release. While TNFalpha directs the development of hyperalgesia, it also directs its resolution. Transformed sensitivity to alpha(2)-adrenergic agonists during hyperalgesia demonstrates a mechanism for therapy.