Assessment of the pulmonary adaptive immune response to Cladosporium cladosporioides infection using an experimental mouse model.

Cladosporium cladosporioides causes asthma and superficial and deep infections, mostly in immunodeficient individuals and animals. This study aimed to investigate whether C. cladosporioides spores can enter the lungs through pulmonary circulation and influence pulmonary immune response. We intravenously injected mice with C. cladosporioides spore suspension and conducted several assays on the lungs. Pulmonary hemorrhage symptoms and congestion were most severe on days 1, 2, and 3 post-inoculation (PI). Extensive inflammatory cell infiltration occurred throughout the period of infection. More spores and hyphae colonizing the lungs were detected on days 1, 2, and 3 PI, and fewer spores and hyphae were observed within 21 d of infection. Numerous macrophages, dendritic cells, and neutrophils were observed on day 5 PI, along with upregulation of CD54, an intercellular adhesion molecule. Th1 and Th2 cells increased after infection; specifically, Th2 cells increased considerably on day 5 PI. These results suggest that days 2 and 5 PI represent the inflammatory peak in the lungs and that the Th2 and Th1 signaling pathways are potentially involved in pulmonary immune responses. In conclusion, the further adaptive immune responses played important roles in establishing effective pulmonary immunity against C. cladosporioides systemic infections based on innate immune responses.

Multidimensional assessment of alveolar T cells in critically ill patients.

Pneumonia represents the leading infectious cause of death in the United States. Foxp3+ regulatory T cells promote recovery from severe pneumonia in mice, but T cell responses in patients with pneumonia remain incompletely characterized because of the limited ability to serially sample the distal airspaces and perform multidimensional molecular assessments on the small numbers of recovered cells. As T cell function is governed by their transcriptional and epigenetic landscape, we developed a method to safely perform high-resolution transcriptional and DNA methylation profiling of T cell subsets from the alveoli of critically ill patients. Our method involves nonbronchoscopic bronchoalveolar lavage combined with multiparameter fluorescence-activated cell sorting, unsupervised low-input RNA-sequencing, and a modified reduced-representation bisulfite sequencing protocol. Here, we demonstrate the safety and feasibility of our method and use it to validate functional genomic elements that were predicted by mouse models. Because of its potential for widespread application, our techniques allow unprecedented insights into the biology of human pneumonia.

Effects of influenza immunization on pneumonia in the elderly.

Influenza virus is a common pathogen implicated in respiratory tract infections, annually affecting up to 20% of the general population, and pneumonia is a leading cause of death after influenza infection. Post-influenza pneumonia is especially common in the elderly and chronically ill patients. The risk of post-influenza pneumonia is significantly increased according to the number of concurrent comorbidities. Vaccination is the primary measure used to abate influenza epidemics and associated complications. In meta-analyses, influenza vaccine significantly reduces pneumonia- and influenza-related hospitalizations, with a vaccine effectiveness of 25-53%. However, considering the poor effectiveness of conventional influenza vaccines in the elderly, several highly immunogenic influenza vaccines have been developed. Further evaluations of the comparative effectiveness of diverse vaccine formulations are warranted to assess their utility for preventing influenza infection, post-influenza pneumonia, and related hospitalization/mortality. Based on cost-effectiveness and budget impact analysis, influenza vaccination strategies should be tailored in the elderly.

Pneumonia Severity Assessment Tools for Predicting Mortality in Patients with Healthcare-Associated Pneumonia: A Systematic Review and Meta-Analysis.

BACKGROUND: In contrast to community-acquired pneumonia (CAP), no specific severity assessment tools have been developed for healthcare-associated pneumonia (HCAP) in clinical practice. OBJECTIVES: In this review, we assessed the clinical significance of severity assessment tools for HCAP. METHODS: We identified related articles from the PubMed database. The eligibility criteria were original research articles evaluating severity scoring tools and reporting the outcomes of mortality in patients with HCAP. RESULTS: Eight articles were included in the meta-analysis. The PORT score and CURB-65 were evaluated in 7 and 8 studies, respectively. Using cutoff values of ≥IV and V for the PORT score, the diagnostic odds ratios (DORs) were 5.28 (2.49-11.17) and 3.76 (2.88-4.92), respectively, and the areas under the curve (AUCs) were 0.68 (0.64-0.72) and 0.71 (0.67-0.75), respectively. Conversely, the AUCs for ≥IV and V were 0.71 (0.67-0.76) and 0.74 (0.70-0.78), respectively, when applied only to nonimmunocompromised patients. In contrast, when using cutoff values of ≥2 and ≥3 for CURB-65, the DORs were 3.35 (2.26-4.97) and 2.65 (2.05-3.43), respectively, and the AUCs were 0.65 (0.61-0.69) and 0.66 (0.62-0.70), respectively. Conversely, the AUCs for ≥2 and ≥3 were 0.65 (0.61-0.69) and 0.68 (0.64-0.72), respectively, when applied only to nonimmunocompromised patients. CONCLUSIONS: The PORT score and CURB-65 do not have substantial power compared with the tools for CAP patients, although the PORT score is more useful than CURB-65 for predicting mortality in HCAP patients. According to our results, however, these tools, especially the PORT score, can be more useful when limited to nonimmunocompromised patients.

Assessment of the short-term toxicity of TiO2 nanofiber in Sprague Dawley rats.

Synthetic nanomaterials have many unique chemical and physical properties, mainly due to their high specific surface area and quantum confinement effect. Specifically, titanium dioxide (TiO2 ) nanomaterial has high stability, anticorrosive, and photocatalytic properties. However, there are concerns over adverse biological effects resulting from bioeffects. This study was to investigate adverse effects associated with acute ingestion of TiO2 nanofiber (TDNF). TDNF was fabricated via electrospinning method, followed by dissolution in water. Six- to seven-week-old male Sprague Dawley rats were exposed to a total of 0, 40, and 60 ppm of TDNF for 2 weeks via oral gavage. Serum total protein and weight gain during the course of this study displayed marginal concentration-dependent alterations. These findings were followed by a global gene expression analysis to identify which transcripts might be responsive to TNDF toxicity. Differentially expressed mRNA levels were dose-dependently higher in animals exposed to TNDF. The majority of the affected genes were biochemically involved in immune response and inflammation. We believe this is due to the fact that TNDF is unable to penetrate the cell and forms phagocytosis sites that trigger inflammatory and immune response. All results taken together, short-term ingestion of TNDF produced marginal effects indicative of inflammation. Finally, the broad gene expression data were validated through quantification of immunoglobulin heavy chain alpha (Igha). Igha gene was upregulated in treated groups, showing similar expression patterns to the global gene expression data.

Prediction Equations Underestimate Resting Energy Expenditure in Patients With End-Stage Cystic Fibrosis.

BACKGROUND: Resting energy expenditure (REE) is increased in patients with cystic fibrosis (CF) with end-stage lung disease due to chronic inflammation and pulmonary infections. After lung transplantation (LTx), energy expenditure is expected to be lower because inflammation will decrease. We assessed the agreement between measured and predicted REE in pre-LTx CF and post-LTx patients with CF and differences in REE in pre-LTx CF and post-LTx patients with CF in a cross-sectional study. METHODS: Included were 12 pre-LTx patients with CF (9 women; median age 31.6 years; interquartile range [IQR], 23.3-40.0) and 12 patients with CF within 2 years after LTx (6 women; median age 33.5 years; IQR, 22.3-40.3). REE was measured in a fasted state using indirect calorimetry. Values were compared with predicted REE calculated by formulas of Harris-Benedict (1919 and 1984), Schofield, and the World Health Organization (1985). A calculated REE between 90% and 110% of REE measured was considered adequate. RESULTS: Prediction equations underestimate REE in at least 75% of pre-LTx and 33% of post-LTx patients with CF. Mean (SD) REE measured by indirect calorimetry was 1735 (251) kcal pre-LTx and 1650 (235) kcal post-LTx ( P = .40). REE expressed per kilogram of fat-free mass (FFM) was 40.5 kcal/kg in pre-LTx patients with CF, which was higher than the 34.3 kcal/kg in post-LTx patients with CF ( P = .01). CONCLUSIONS: Prediction equations underestimate REE in patients with end-stage CF. REE per kg of FFM is lower post-LTx than pre-LTx in patients with CF. Measurement of REE is recommended for patients with CF, especially pre-LTx, to optimize energy requirements for improving nutrition status.

Rates of pneumonia among children and adults with chronic medical conditions in Germany.

BACKGROUND: The objective of this study is to evaluate rates of all-cause pneumonia among "at-risk" and "high-risk" children and adults in Germany-in comparison with age-stratified healthy counterparts-during the period following the 2006 recommendation for universal immunization of infants with pneumococcal conjugate vaccine. METHODS: Retrospective cohort design and healthcare claims information for 3.4 M persons in Germany (2009-2012) were employed. Study population was stratified by age and risk profile (healthy, "at-risk" [with chronic medical conditions], and "high-risk" [immunocompromised]). At-risk and high-risk conditions, as well as episodes of all-cause pneumonia, were identified via diagnosis, procedure, and drug codes. RESULTS AND DISCUSSION: Rates of all-cause pneumonia were 1.7 (95 % CI 1.7-1.8) to 2.5 (2.4-2.5) times higher among children and adults with at-risk conditions versus healthy counterparts, and 1.8 (1.8-1.9) to 4.1 (4.0-4.2) times higher among children and adults with high-risk conditions. Rates of all-cause pneumonia among at-risk persons increased in a graded and monotonic fashion with increasing numbers of conditions (i.e., risk stacking). CONCLUSIONS: An increased risk for all-cause pneumonia in German children and adults with a spectrum of medical conditions persists in the era of widespread pneumococcal vaccination, and pneumonia risk in persons with ≥2 at-risk conditions is comparable or higher than those with high-risk conditions.

Inhibition of airway inflammation by the roots of Angelica decursiva and its constituent, columbianadin.

ETHNOPHARMACOLOGICAL RELEVANCE: The roots of Angelica decursiva Fr. Et Sav (Umbelliferae) have been frequently used in traditional medicine as anti-inflammatory, antitussive, analgesic agents and expectorant, especially for treating cough, asthma, bronchitis and upper respiratory tract infections. To establish the scientific rationale for the clinical use of Angelica decursiva and to identify new agents for treating inflammatory lung disorders, pharmacological evaluation of the roots of Angelica decursiva and the isolated constituents was performed. METHODS: In vitro study was carried out using two lung cells, lung epithelial cells (A549) and alveolar macrophages (MH-S). The inflammatory markers such as IL-6 and nitric oxide (NO) for each cell line were examined. For in vivo study, a mouse model of lipopolysaccharide (LPS)-induced acute lung injury was used and the effects on lung inflammation were established by measuring the cell numbers in bronchoalveolar lavage fluid (BALF) and by histological observation. RESULTS: Water and 70% ethanol extracts of the roots of Angelica decursiva showed considerable inhibitory activity against LPS-induced lung inflammation in mice following oral administration at a dose of 400 mg/kg. Five coumarin derivatives including columbianadin, umbelliferone, umbelliferone 6-carboxylic acid, nodakenin and nodakenetin were isolated. Among the isolated compounds, columbianadin was found to possess strong inhibitory activity against the inflammatory response of IL-1ß-treated A549 cells and LPS-treated MH-S cells. Columbianadin was found to inhibit NO production by down-regulation of inducible NO synthase. Moreover, columbianadin was also proved to possess significant inhibitory activity against LPS-induced lung inflammation following oral administration at a dose of 20-60 mg/kg. CONCLUSIONS: The roots of Angelica decursiva were proved to be effective in the treatment of lung inflammation. Columbianadin can be a potential new agent for treating inflammatory lung disorders.

Quantitative assessment of nanoparticle surface hydrophobicity and its influence on pulmonary biocompatibility.

To date, the role of nanoparticle surface hydrophobicity has not been investigated quantitatively in relation to pulmonary biocompatibility. A panel of nanoparticles spanning three different biomaterial types, pegylated lipid nanocapsules, polyvinyl acetate (PVAc) and polystyrene nanoparticles, were characterized for size, surface charge, and stability in biofluids. Surface hydrophobicity of five nanoparticles (50-150nm) was quantified using hydrophobic interaction chromatography (HIC) and classified using a purpose-developed hydrophobicity scale: the HIC index, range from 0.00 (hydrophilic) to 1.00 (hydrophobic). This enabled the relationship between the nanomaterial HIC index value and acute lung inflammation after pulmonary administration to mice to be investigated. The nanomaterials with low HIC index values (between 0.50 and 0.64) elicited little or no inflammation at low (22cm(2)) or high (220cm(2)) nanoparticle surface area doses per animal, whereas equivalent surface area doses of the two nanoparticles with high HIC index values (0.88-0.96) induced neutrophil infiltration, elevation of pro-inflammatory cytokines and adverse histopathology findings. In summary, a HIC index is reported that provides a versatile, discriminatory, and widely available measure of nanoparticle surface hydrophobicity. The avoidance of high (HIC index>~0.8) surface hydrophobicity appears to be important for the design of safe nanomedicines for inhalation therapy.

System-based identification of toxicity pathways associated with multi-walled carbon nanotube-induced pathological responses.

The fibrous shape and biopersistence of multi-walled carbon nanotubes (MWCNT) have raised concern over their potential toxicity after pulmonary exposure. As in vivo exposure to MWCNT produced a transient inflammatory and progressive fibrotic response, this study sought to identify significant biological processes associated with lung inflammation and fibrosis pathology data, based upon whole genome mRNA expression, bronchoaveolar lavage scores, and morphometric analysis from C57BL/6J mice exposed by pharyngeal aspiration to 0, 10, 20, 40, or 80 µg MWCNT at 1, 7, 28, or 56 days post-exposure. Using a novel computational model employing non-negative matrix factorization and Monte Carlo Markov Chain simulation, significant biological processes with expression similar to MWCNT-induced lung inflammation and fibrosis pathology data in mice were identified. A subset of genes in these processes was determined to be functionally related to either fibrosis or inflammation by Ingenuity Pathway Analysis and was used to determine potential significant signaling cascades. Two genes determined to be functionally related to inflammation and fibrosis, vascular endothelial growth factor A (vegfa) and C-C motif chemokine 2 (ccl2), were confirmed by in vitro studies of mRNA and protein expression in small airway epithelial cells exposed to MWCNT as concordant with in vivo expression. This study identified that the novel computational model was sufficient to determine biological processes strongly associated with the pathology of lung inflammation and fibrosis and could identify potential toxicity signaling pathways and mechanisms of MWCNT exposure which could be used for future animal studies to support human risk assessment and intervention efforts.

Obesity and the risk and outcome of infection.

The interactions between obesity and infectious diseases have recently received increasing recognition as emerging data have indicated an association between obesity and poor outcome in pandemic H1N1 influenza infection. Obesity is an established risk factor for surgical-site infections, nosocomial infections, periodontitis and skin infections. Several studies indicate that acute pancreatitis is more severe in the obese. Data are controversial and limited as regards the association between obesity and the risk and outcome of community-acquired infections such as pneumonia, bacteremia and sepsis and obesity and the course of HIV infection. As the cause-effect relationship between obesity and infection remains obscure in many infectious diseases, further studies are warranted. The consequences of obesity may have substantial effects on the global burden of infectious diseases.

Pneumococcal polysaccharide vaccination for adults: new perspectives for Europe.

Vaccination is the only public-health measure likely to reduce the burden of pneumococcal diseases. In 2010, a group of European experts reviewed evidence on the burden of pneumococcal disease and the immunogenicity, clinical effectiveness and cost-effectiveness of vaccination with 23-valent pneumococcal polysaccharide vaccine (PPV23). They also considered issues affecting the future use of PPV23 and pneumococcal conjugate vaccines in the elderly and adults at high risk of pneumococcal disease. PPV23 covers 80-90% of the serotypes responsible for invasive pneumococcal disease in Europe. Primary vaccination and revaccination with PPV23 are well tolerated, induce robust, long-lasting immune responses in elderly adults and are cost effective. Ensuring protection against pneumococcal disease requires monitoring of the changing epidemiology of pneumococcal serotypes causing invasive pneumococcal disease and improving vaccine coverage. In the future, it will be critically important for pneumococcal vaccination recommendations for elderly adults to be based on comparative evaluations of PPV23 and newer pneumococcal conjugate vaccines with regard to their long-term immunogenicity, clinical effectiveness and cost-effectiveness.

Cost effectiveness of heptavalent pneumococcal conjugate vaccine in populations of high risk in Colombia / Costo efectividad de la vacuna conjugada heptavalente de neumococo en poblaciones de alto riesgo en Colombia: el caso de la vacunación en niños de bajo peso al nacer

Objective: To estimate the economic impact of the introduction of heptavalent pneumococcal conjugate vaccine (PCV-7) in high risk populations of Colombia. Methods: A full economic evaluation was done regarding potential introduction of PCV-7. A cost-effectiveness study from the perspective of the third payer was done using a Decision Model. The model considered two alternatives: with and without vaccination. As measurement of results the avoided events were taken [cases, hospitalizations, deaths and Life-Years Saved (LYS)]. In addition the net costs and the incremental cost-effectiveness ratio (ICER) were evaluated. Results: In a cohort of 70 thousand children of under 2 years old in situation of high risk, can generate 532 deaths that would produce a little more than 21 thousand Years of Life Lost (YLL) with costs between 7.7 and 13.3 million dollars. If we vaccinate this same cohort the deaths can be reduced to 355, and the costs of burden of disease would be between 5.7 and 10 million dollars. It is estimated a reduction of 25% of the costs of burden of disease and of 33% of the deaths. In addition the ICER by YLS would be between 590 and 762 dollars. Conclusion: The introduction of the Heptavalent Pneumococcal Conjugate Vaccine in populations of high risk is highly cost effective in Colombia.

Objetivo: Evaluar económicamente la introducción de la vacuna heptavalente de neumococo en poblaciones de alto riesgo en Colombia. Métodos: Se realizó un análisis de costo-efectividad desde la perspectiva del tercer pagador utilizando un modelo de decisiones que consideró dos alternativas: con y sin programa de vacunación. Como medida de resultados se tomaron los eventos evitados [casos, hospitalizaciones, muertes y años de vida salvados (AVS)]. Además, se valoraron los costos netos y la razón de costo-efectividad incremental (RCEI). Resultados: En una cohorte de 70 mil niños menores de dos años en situación de alto riesgo (bajo peso al nacer), se puede generar 532 muertes que producirían un poco más de 21 mil años de vida perdidos. Los costos de atención estarían entre 7,7 y 13,3 millones de dólares. Si vacunásemos esta misma cohorte con la vacuna conjugada heptavalente las muertes se reducirían a 355 y los costos de la carga estarían entre 5,7 y 10 millones de dólares. Es decir, una reducción cerca de 25% de los costos de la carga y 33% de las muertes. Además el CEI por AVS estaría entre 590 y 762 dólares del año 2006. Conclusiones: La introducción de la vacuna contra neumococo en poblaciones de alto riesgo (bajo peso al nacer) en Colombia es altamente costo-efectiva.

Assessment of airway inflammation using sputum, BAL, and endobronchial biopsies in current and ex-smokers with established COPD.

RATIONALE: Smoking effects on physiological and gross pathology in chronic obstructive pulmonary disease (COPD) are relatively well described. However, there is little known in COPD about the detailed interrelationships between lung function and inflammatory profiles in different airway compartments from the same individual and whether airway inflammation in these different compartments differs in ex- and current smokers with established COPD. OBJECTIVES: We compared sputum, bronchoalveolar (BAL), and airway wall inflammatory profiles in current versus ex-smokers and related this to smoking intensity and lung function in 17 current and 17 ex-smokers with mild to moderate COPD. RESULTS: Current smokers had more sputum mast cells (% differential and absolute numbers), whereas ex-smokers had increased sputum neutrophils. In BAL, there was a significant increase in eosinophils in current smokers, but ex-smokers had significantly increased neutrophils, lymphocytes, and epithelial cells. There were no cell profile differences observed in airway biopsies between current and ex-smokers and there were no correlations between the individual inflammatory cell populations in any of the airway compartments. In current smokers only, smoking intensity was negatively correlated with lung function, and associated with a reduction in overall cellularity of both sputum and BAL. CONCLUSION: Airway inflammation persists in ex-smokers with COPD, but differs from COPD current smokers. The impact of smoking appears to vary in different airway compartments and any direct relationships between cellularity and lung function tended to be negative, ie, worse lung function indicated the presence of fewer cells.

Cost-effectiveness of introducing the conjugated pneumococcal vaccine to routine free immunizations for infants in Lazio, Italy.

OBJECTIVE: To examine the health outcomes and costs of a hypothetical pneumococcal vaccination campaign among the general infant population in the Lazio region (Italy). METHODS: We developed a model simulating direct medical costs and health outcomes of vaccinating infants with conjugated pneumococcal vaccine (PCV-7) compared to the costs (in and outpatient) of treating the disease, from a public health service perspective. According to vaccine trials' outcomes, we considered vaccine effectiveness in preventing part of the invasive pneumococcal disease (IPD), pneumonia of any aetiology, and acute otitis moedia. Age-specific incidence, mortality and health care costs came from local surveillance and surveys; the vaccine costs euro40/dose. Annual budgetary impact and macro-health benefits were predicted for 2005-2014. Cost-effectiveness was expressed as net healthcare costs per disability-adjusted life-year (DALY) gained. RESULTS: After 10 years, five cases of meningitis, 20 IPD, 933 pneumonia, 406 pneumonia-related hospitalisations, and 3160 otitis cases would be averted annually by vaccinating. The annual cost of vaccination would be euro4.9m, and annual costs averted would be euro1.4m. Additional healthcare costs of a mass vaccination would decrease over time from euro5.1m to euro3.5m per year. At baseline, net cost per averted DALY was euro18.0k, if health benefits are not discounted, and euro51.7k adopting a 3.5% discount rate; it was 12% lower with a hypothesis of high IPD incidence and 68% lower if the vaccine cost 50% less. CONCLUSIONS: The cost of the vaccine makes the campaign more expensive than today's recommended infant vaccinations. Nevertheless, the cost-effectiveness of introducing PCV-7 in Lazio compares favourably with previous estimates in similar countries.

Airway inflammation contributes to health status in COPD: a cross-sectional study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow limitation and airway inflammation, accompanied by decreased health status. It is still unknown which factors are responsible for the impaired health status in COPD. We postulated that airway inflammation negatively contributes to health status in COPD. METHODS: In 114 COPD patients (99 male, age: 62 +/- 8 yr, 41 [31-55] pack-years, no inhaled or oral corticosteroids, postbronchodilator FEV1: 63 +/- 9% pred, FEV1/IVC: 48 +/- 9%) we obtained induced sputum and measured health status (St. George's respiratory questionnaire (SGRQ)), postbronchodilator FEV1, hyperinflation (RV/TLC), and airway hyperresponsiveness to methacholine (PC20). Sputum was induced by hypertonic saline and differential cell counts were obtained in 102 patients. RESULTS: Univariate analysis showed that SGRQ total and symptom score were positively associated with % sputum macrophages (r = 0.20, p = 0.05; and r = 0.20, p = 0.04, respectively). Multiple regression analysis confirmed these relationships, providing significant contributions of % sputum macrophages (B = 0.25, p = 0.021) and RV/TLC (B = 0.60, p = 0.002) to SGRQ total score. Furthermore, SGRQ symptom score was associated with % sputum macrophages (B = 0.30, p = 0.03) and RV/TLC (B = 0.48, p = 0.044), whilst SGRQ activity score was associated with % sputum macrophages (B = 0.46, p = 0.002), RV/TLC (B = 0.61, p = 0.015), and PC20 (B = -9.3, p = 0.024). Current smoking and FEV1 were not significantly associated with health status in the multiple regression analysis. CONCLUSION: We conclude that worse health status in COPD patients is associated with higher inflammatory cell counts in induced sputum. Our findings suggest that airway inflammation and hyperinflation independently contribute to impaired health status in COPD. This may provide a rationale for anti-inflammatory therapy in this disease.

Biomonitoring for assessment of organic dust-induced lung inflammation.

Inhalation exposure to particulate matter containing endotoxin (or lipopolysaccharide (LPS)) occurs in a variety of occupations. Nasal lavage and induced sputum have been used to evaluate lung inflammation resulting from such exposures. Whole blood assay (WBA) measures cytokine production of leukocytes after ex vivo stimulation with LPS. The present study examined the effectiveness of WBA for evaluating inflammatory responses and susceptibility. C3HeB/FEJ mice were tolerised by LPS injection or sham tolerised with saline. Animals then inhaled either swine barn dust extract containing endotoxin or saline. Bronchoalveolar lavage (BAL) fluid was assayed for leukocyte counts and pro-inflammatory cytokines (interleukin-6, tumour necrosis factor-alpha). Whole blood was stimulated with 10 or 100 ng.mL(-1) of LPS, incubated for 5 or 18 h and assayed for cytokines. Barn dust-exposed groups revealed significantly higher total cells, neutrophils and cytokines in BAL compared with saline-exposed groups. Animals tolerised to LPS and exposed to barn dust demonstrated lower cellular and cytokine BAL responses. Similarly, WBA yielded significantly elevated cytokines with barn dust exposure and reduced responses with tolerisation. This study demonstrates the efficacy of whole blood assay as a biomarker of inhalation exposure to inflammatory agents and its use for assessing susceptibility to organic dust-induced lung inflammation.

Energy cost of infection burden: an approach to understanding the dynamics of host-pathogen interactions.

A mathematical model of long-term immune defense against infection was used to estimate the energy involved in the principal processes of immune resistance during periods of health and infection. From these values, an optimal level of energy was determined for immune response depending on infection burden. The present findings suggest that weak but prevalent pathogens lead to latent or chronic infection, whereas more virulent but less prevalent pathogens result in acute infection. This energy-based approach offers insight into the mechanisms of immune system adaptation leading to the development of chronic infectious diseases and immune deficiencies.

Multiple contributing roles for NOS2 in LPS-induced acute airway inflammation in mice.

Acute lung inflammation and injury were induced by intranasal instillation of lipopolysaccharide (LPS) in normal and type 2 nitric oxide synthase (NOS2)-deficient (NOS2-/-) C57BL/6 mice. LPS-induced increases in extravasated airway neutrophils and in lung lavage fluid of TNF-alpha and macrophage inflammatory protein-2 were markedly lower in NOS2-/- than in wild-type mice, indicating that NOS2-derived nitric oxide (NO.) participates in inflammatory cytokine production and neutrophil recruitment. Instillation of LPS also increased total lung lavage protein and induced matrix metalloproteinase-9 and mucin 5AC, as indexes of lung epithelial injury and/or mucus hyperplasia, and increased tyrosine nitration of lung lavage proteins, a marker of oxidative injury. All these responses were less pronounced in NOS2-/- than in wild-type mice. Inhibition of NOS activity also suppressed production of TNF-alpha and macrophage inflammatory protein-2 by LPS-stimulated mouse alveolar MH-S macrophages, and this was restored by NO. donors, illustrating involvement of NO. in macrophage cytokine signaling. Oligonucleotide microarray (GeneChip) analysis of global lung gene expression revealed that LPS inhalation induced a range of transcripts encoding proinflammatory cytokines and chemokines, stress-inducible factors, and other extracellular factors and suppressed mRNAs encoding certain cytoskeletal proteins and signaling proteins, responses that were generally attenuated in NOS2-/- mice. Comparison of both mouse strains revealed altered expression of several cytoskeletal proteins, cell surface proteins, and signaling proteins in NOS2-/- mice, changes that may partly explain the reduced responsiveness to LPS. Collectively, our results suggest that NOS2 participates in the acute inflammatory response to LPS by multiple mechanisms: involvement in proinflammatory cytokine signaling and alteration of the expression of various genes that affect inflammatory-immune responses to LPS.