Early Identification of Acute Lung Injury in a Porcine Model of Hemorrhagic Shock.

BACKGROUND: Acute lung injury (ALI) is a frequent complication after severe trauma. Lung-protective ventilation strategies and damage control resuscitation have been proposed for the prevention of ALI; however, there are no clinical or laboratory parameters to predict who is at risk of developing ALI after trauma. In the present study, we explored pulmonary inflammatory markers as a potential predictor of ALI using a porcine model of hemorrhagic shock. MATERIALS AND METHODS: Female swine were randomized to mechanical ventilation with low tidal volume (VT) (6 mL/kg) or high VT (12 mL/kg). After equilibration, animals underwent pressure-controlled hemorrhage (mean arterial pressure [MAP] 35 ± 5 mmHg) for 1 h, followed by resuscitation with fresh whole blood or Hextend. They were maintained at MAP of 50 ± 5 mmHg for 3 h in the postresuscitation phase. Bronchoalveolar lavage fluids were collected hourly and analyzed for inflammatory markers. Lung samples were taken, and porcine neutrophil antibody staining was used to evaluate the presence of neutrophils. ELISA evaluated serum porcine surfactant protein D levels. Sham animals were used as negative controls. RESULTS: Pigs that underwent hemorrhagic shock had higher heart rates, lower cardiac output, lower MAPs, and worse acidosis compared with sham at the early time points (P < 0.05 each). There were no significant differences in central venous pressure or pulmonary capillary wedge pressure between groups. Pulmonary neutrophil infiltration, as defined by neutrophil antibody staining on lung samples, was greater in the shock groups regardless of resuscitation fluid (P < 0.05 each). Bronchoalveolar lavage fluid neutrophil levels were not different between groups. There were no differences in levels of porcine surfactant protein D between groups at any time points, and the levels did not change over time in each respective group. CONCLUSIONS: Our study demonstrates the reproducibility of a porcine model of hemorrhagic shock that is consistent with physiologic changes in humans in hemorrhagic shock. Pulmonary neutrophil infiltration may serve as an early marker for ALI; however, the practicality of this finding has yet to be determined.

Simvastatin Therapy and Bronchoalveolar Lavage Fluid Biomarkers in Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is a progressive disease underlain by airway inflammation. Despite trials with new generations of anti-inflammatory drugs to alleviate the disease burden, the effective curative treatment remains elusive. In this context, the aim of this study was to assess the influence of simvastatin, a leading member of the family of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, known to display anti-inflammatory and immunomodulatory activity, on symptoms and lung function, as well as the proportion of inflammatory cells, cytokines, proteolytic enzymes, and surfactant protein D (SP-D) content in bronchoalveolar lavage fluid (BALF) in COPD patients. There were 50 patients with moderate-to-severe airway obstructions included into the study, subdivided into simvastatin-treated (Zocor - MSD; 40 mg daily) and control simvastatin-untreated groups, other treatment being equal. Pulmonary functions tests and bronchofiberoscopy with BALF procedure were performed before and after 3-month-long treatment in both groups. The major finding was that simvastatin treatment caused a distinct increase in the airway content of SP-D. Further effects, albeit smaller in magnitude, consisted of reductions in the proportion of airway neutrophils and in MMP-9 content, all with a benefit of improved score in the disease activity assessment test. There were no appreciable changes noted in lung function or dyspnea perception, which could be ascribed to simvastatin treatment. We conclude that statin's anti-inflammatory and surfactant homeostasis preserving properties may offer promise as an adjunctive treatment in COPD patients. The SP-D content in BALF has a potential to become a marker of COPD inflammatory activity and treatment monitoring.

Pirfenidone Improves Familial Idiopathic Pulmonary Fibrosis without Affecting Serum Periostin Levels.

Background: Antifibrotic agents have been approved for the treatment of idiopathic pulmonary fibrosis (IPF). However, the efficacy of these drugs in the treatment of familial IPF (FIPF) has not been previously reported. Case presentation: We report the case of a 77-year-old man with FIPF, successfully treated with pirfenidone. His uncle died due to IPF, and his niece was diagnosed with the disease. He had worsening dyspnea two months prior to admission to our hospital. Upon admission, he had desaturation when exercising and broad interstitial pneumonia. Administration of pirfenidone improved his dyspnea, desaturation, and the reticular shadow on his chest radiograph. Increased fibrotic marker levels KL-6 and SP-D were also normalized in six months; treatment had no effect on his serum periostin level. Pirfenidone has been effective for over two years. Conclusion: Antifibrotic agents such as pirfenidone may be useful for the management of FIPF, as well as cases of sporadic IPF.

[PROGNOSTIC VALUE OF BLOOD AND BRONCHOALVEOLAR LAVAGE FLUIDS BIOMARKERS FOR IDIOPATHIC PULMONARY FYBROSIS (REVIEW)].

The article reveals the modern aspects of IPF pathogenesis in with an emphasis on the main proposed prognostic biomarkers. IPF remains the leader among diseases with unknown etiology, the diagnosis and management of which are not very successful, despite the obvious progress in molecular medicine. There is presented analysis of the significance of IPF potential biomarkers and their concentrations in the blood and bronchoalveolar lavage fluids (BAL): endothelin-1, CC-chemokine ligand 18, interleukin-1, surfactant protein SP-D in the review. The role of their changing levels in the blood and BAL for assessing the course of the IPF and its prognosis, as well as the prevailing importance of the polymorphism of the genes encoding them, is shown. Obviously, the progressive accumulation of fibroblast-myofibroblast cells in the lungs IPF patients worsens the prognosis of disease, forms its own environment with a set of cytokines, growth factors, collagen, fibronectin in the extracellular matrix of fibrous lungs. The insufficient amount of studies in the face of the rarity of the disease leaves a lot of controversial issues for solution in the future. Obviously, to assess the prognosis of IPF mortality, it is necessary to include a very large number of patients, to extend the observation period, which increases their cost and reduces the opportunities and desire of pharmaceutical companies to participate in these studies.

Neuromuscular blockade is associated with the attenuation of biomarkers of epithelial and endothelial injury in patients with moderate-to-severe acute respiratory distress syndrome.

BACKGROUND: Neuromuscular blockade (NMB) is a therapy for acute respiratory distress syndrome (ARDS). However, the mechanism by which NMB may improve outcome for ARDS patients remains unclear. We sought to determine whether NMB attenuates biomarkers of epithelial and endothelial lung injury and systemic inflammation in ARDS patients, and whether the association is dependent on tidal volume size and the initial degree of hypoxemia. METHODS: We performed a secondary analysis of patients enrolled in the ARDS network low tidal volume ventilation (ARMA) study. Our primary predictor variable was the number of days receiving NMB between study enrollment and day 3. Our primary outcome variables were the change in concentration of biomarkers of epithelial injury (serum surfactant protein-D (SP-D)), endothelial injury (von Willebrand factor (VWF)), and systemic inflammation (interleukin (IL)-8). Multivariable regression analysis was used to compare the change in biomarker concentration controlling for multiple covariates. Patients were stratified by treatment arm (12 versus 6 cm3/kg) and by an initial arterial oxygen tension (PaO2) to fractional inspired oxygen (FiO2) (P/F) ratio of 120. RESULTS: A total of 446 (49%) patients had complete SP-D, VWF, and IL-8 measurements on study enrollment and day 3. After adjusting for baseline differences, each day of NMB was associated with a decrease in SP-D (-23.7 ng/ml/day, p = 0.029), VWF (-33.5% of control/day, p = 0.015), and IL-8 (-362.6 pg/ml/day, p = 0.030) in patients with an initial P/F less than or equal to 120 and receiving low tidal volume ventilation. However, patients with a P/F ratio of greater than 120 or receiving high tidal volume ventilation had either no change or an increase in SP-D, WVF, or IL-8 concentrations. CONCLUSION: NBM is associated with decreased biomarkers of epithelial and endothelial lung injury and systemic inflammation in ARDS patients receiving low tidal volume ventilation and those with a P/F ratio less than or equal to 120.

Sputum neutrophils are elevated in smelter workers, and systemic neutrophils are associated with rapid decline in FEV1.

OBJECTIVES: In a previous study on smelter workers we, found significant relationship between exposure to dust and accelerated annual decline in forced expiratory volume in 1 s (FEV1). In this cross-sectional study at the end of a follow-up, we aimed to investigate the possible association between annual decline in FEV1 and markers of airways, and systemic inflammation in smelter workers. METHODS: Employees (n=76 (27 current smokers)) who had been part of a longitudinal study (9-13 years) that included spirometry (>6 measurements) and respiratory questionnaires, performed induced sputum, exhaled NO and had blood drawn. Participants with annual decline in FEV1≥45 mL were compared with participants with annual decline <45 mL; also 26 non-exposed controls were included. RESULTS: Compared with non-exposed controls, smelter workers demonstrated a significantly increased percentage of neutrophils (mean (SD)) (57% (17) vs 31% (15)) and matrix metalloproteinases 8 (MMP-8) levels in sputum, and MMP-9, surfactant protein D (SpD) and transforming growth factor ß (TGFb) levels in blood. A significant association in FEV1≥45 mL was found for blood neutrophils when controlling for smoking habits (OR=1.7 (95% CI 1.0 to 2.8), p=0.045). Airway and blood protein markers were not associated with annual decline in FEV1. CONCLUSIONS: All workers displayed airway and systemic inflammation characterised by increased levels of neutrophils and MMP-8 in sputum, and MMP-9, SpD and TGFß in blood compared with non-exposed controls. Blood neutrophils in particular were significantly elevated in those workers with the most rapid decline in lung function. A similar observation was not seen with airway neutrophils. In the present study, we were able to identify systemic but not airway inflammatory markers that can predict increased decline in FEV1 in smelter workers.

[Levels of surfactant proteins A and D in bronchoalveolar lavage fluid of children with pneumonia and their relationships with clinical characteristics].

OBJECTIVE: To observe the levels of pulmonary surfactant proteins A and D (SP-A, SP-D) in bronchoalveolar lavage fluid (BALF) of children with pneumonia, and to explore their relationships with clinical characteristics. METHODS: Thirty-five children with pneumonia were enrolled in this study. Differential cell counts were obtained by Countstar counting board. The levels of SP-A and SP-D in BALF were detected using ELISA. RESULTS: In children with pneumonia, SP-D levels were significantly higher than SP-A levels (P<0.001). SP-D levels were negatively correlated with the neutrophil percentage in BALF (r(s)=-0.5255, P<0.01). SP-D levels in BALF in children with increased blood C-reactive protein levels (>8 mg/L) were significantly lower than in those with a normal level of C-reactive protein (P<0.05). Compared with those in children without wheezing, SP-D levels in children with wheezing were significantly lower (P<0.01). There was no correlation between SP-A levels and clinical characteristics. CONCLUSIONS: SP-D levels in BALF are significantly higher than SP-A levels, and have a certain correlation with clinical characteristics in children with pneumonia. As a protective factor, SP-D plays a more important role than SP-A in regulating the immune and inflammatory responses.

A mathematical model to predict protein wash out kinetics during whole-lung lavage in autoimmune pulmonary alveolar proteinosis.

Whole-lung lavage (WLL) remains the standard therapy for pulmonary alveolar proteinosis (PAP), a process in which accumulated surfactants are washed out of the lung with 0.5-2.0 l of saline aliquots for 10-30 wash cycles. The method has been established empirically. In contrast, the kinetics of protein transfer into the lavage fluid has not been fully evaluated either theoretically or practically. Seventeen lungs from patients with autoimmune PAP underwent WLL. We made accurate timetables for each stage of WLL, namely, instilling, retaining, draining, and preparing. Subsequently, we measured the volumes of both instilled saline and drained lavage fluid, as well as the concentrations of proteins in the drained lavage fluid. We also proposed a mathematical model of protein transfer into the lavage fluid in which time is a single variable as the protein moves in response to the simple diffusion. The measured concentrations of IgG, transferrin, albumin, and ß2-microglobulin closely matched the corresponding theoretical values calculated through differential equations. Coefficients for transfer of ß2-microglobulin from the blood to the lavage fluid were two orders of magnitude higher than those of IgG, transferrin, and albumin. Simulations using the mathematical model showed that the cumulative amount of eliminated protein was not affected by the duration of each cycle but dependent mostly on the total time of lavage and partially on the volume instilled. Although physicians have paid little attention to the transfer of substances from the lung to lavage fluid, WLL seems to be a procedure that follows a diffusion-based mathematical model.

Distinct compartmentalization of SP-A and SP-D in the vasculature and lungs of patients with idiopathic pulmonary fibrosis.

BACKGROUND: Surfactant proteins SP-A and SP-D are useful biomarkers in diagnosis, monitoring, and prognosis of idiopathic pulmonary fibrosis (IPF). Despite their high structural homology, their serum concentrations often vary in IPF patients. This retrospective study aimed to investigate distinct compartmentalization of SP-A and SP-D in the vasculature and lungs by bronchoalveolar lavage fluid (BALF)/serum analysis, hydrophilicity and immunohistochemistry. METHODS: We included 36 IPF patients, 18 sarcoidosis (SAR) patients and 20 healthy subjects. Low-speed centrifugal supernatants of BALF (Sup-1) were obtained from each subject. Sera were also collected from each patient. Furthermore, we separated Sup-1 of IPF patients into hydrophilic supernatant (Sup-2) and hydrophobic precipitate (Ppt) by high-speed centrifugation. We measured SP-A and SP-D levels of each sample with the sandwich ELISA technique. We analyzed the change of the BALF/serum level ratios of the two proteins in IPF patients and their hydrophilicity in BALF. The distribution in the IPF lungs was also examined by immunohistochemical staining. RESULTS: In BALF, SP-A levels were comparable between the groups; however, SP-D levels were significantly lower in IPF patients than in others. Although IPF reduced the BALF/serum level ratios of the two proteins, the change in concentration of SP-D was more evident than SP-A. This suggests a higher disease impact for SP-D. Regarding hydrophilicity, although more than half of the SP-D remained in hydrophilic fractions (Sup-2), almost all of the SP-A sedimented in the Ppt with phospholipids. Hydrophilicity suggests that SP-D migrates into the blood more easily than SP-A in IPF lungs. Immunohistochemistry revealed that SP-A was confined to thick mucus-filling alveolar space, whereas SP-D was often intravascular. This data also suggests that SP-D easily leaks into the bloodstream, whereas SP-A remains bound to surfactant lipids in the alveolar space. CONCLUSIONS: The current study investigated distinct compartmentalization of SP-A and SP-D in the vasculature and lungs. Our results suggest that serum levels of SP-D could reflect pathological changes of the IPF lungs more incisively than those of SP-A.

Idiopathic pulmonary fibrosis: from epithelial injury to biomarkers--insights from the bench side.

Idiopathic pulmonary fibrosis (IPF) is the most frequent fibrotic diffuse parenchymal lung disease. Its prognosis is devastating: >50% of the patients die within 3 years after diagnosis. Options for the treatment of IPF are limited and lung transplantation is the only 'curative' therapy. Currently, in the absence of validated indicators of disease progression/activity and diagnostic tools, the clinical management of IPF remains a major challenge. A better understanding of the pathogenesis of IPF is critical for the identification of new therapeutic targets as well as molecules that may serve as surrogate markers for clinically significant endpoints. The current paradigm on the mechanisms leading from a normal to a fibrotic lung postulates that chronic epithelial lesion leads to aberrant wound healing activation, which is characterized by deregulated fibroblast proliferation and activation together with an uncontrolled extracellular matrix synthesis. In this review, we shed light on the role of epithelial cell damage in the pathogenesis of fibrosis. Finally, we examine the markers of epithelial damage and their potential use as biomarkers and the future of this continuously expanding field.

Surfactant protein-D regulates effector cell function and fibrotic lung remodeling in response to bleomycin injury.

RATIONALE: Surfactant protein (SP)-D and SP-A have been implicated in immunomodulation in the lung. It has been reported that patients with idiopathic pulmonary fibrosis (IPF) often have elevated serum levels of SP-A and SP-D, although their role in the disease is not known. OBJECTIVES: The goal of this study was to test the hypothesis that SP-D plays an important role in lung fibrosis using a mouse model of fibrosis induced by bleomycin (BLM). METHODS: Triple transgenic inducible SP-D mice (iSP-D mice), in which rat SP-D is expressed in response to doxycycline (Dox) treatment, were administered BLM (100 U/kg) or saline subcutaneously using miniosmotic pumps. MEASUREMENTS AND MAIN RESULTS: BLM-treated iSP-D mice off Dox (SP-D off) had increased lung fibrosis compared with mice on Dox (SP-D on). SP-D deficiency also increased macrophage-dominant cell infiltration and the expression of profibrotic cytokines (transforming growth factor [TGF]-ß1, platelet-derived growth factor-AA). Alveolar macrophages isolated from BLM-treated iSP-D mice off Dox (SP-D off) secreted more TGF-ß1. Fibrocytes, which are bone marrow-derived mesenchymal progenitor cells, were increased to a greater extent in the lungs of the BLM-treated iSP-D mice off Dox (SP-D off). Fibrocytes isolated from BLM-treated iSP-D mice off Dox (SP-D off) expressed more of the profibrotic cytokine TGF-ß1 and more CXCR4, a chemokine receptor that is important in fibrocyte migration into the lungs. Exogenous SP-D administered intratracheally attenuated BLM-induced lung fibrosis in SP-D(-/-) mice. CONCLUSIONS: These data suggest that alveolar SP-D regulates numbers of macrophages and fibrocytes in the lungs, profibrotic cytokine expression, and fibrotic lung remodeling in response to BLM injury.

Protective effect of curcumin on acute lung injury induced by intestinal ischaemia/reperfusion.

The aim of this study is to evaluate the role of curcumin on acute lung injury induced by intestinal ischaemia/reperfusion (I/R). A total of 30 male Wistar albino rats were divided into 3 groups: sham, I/R, and I/R + curcumin; each group contains 10 animals. Sham group animals underwent laparotomy without I/R injury. After I/R groups animals underwent laparotomy, 1 h of superior mesenteric artery ligation were followed by 1 h of reperfusion. In the curcumin group, 3 days before I/R, curcumin (100 mg/kg) was administered by gastric gavage. All animals were killed at the end of reperfusion and lung tissue samples were obtained for biochemical and histopathological investigation in all groups. To date, no more biochemical and histopathological changes on intestinal I/R injury in rats by curcumin treatment have been reported. Curcumin treatment significantly decreased the elevated tissue malondialdehyde levels and increased reduced superoxide dismutase, and glutathione peroxidase enzyme activities in lung tissue samples. Intestinal I/R caused severe histopathological injury including oedema, haemorrhage, increased thickness of the alveolar wall, and infiltration of inflammatory cells into alveolar spaces. Curcumin treatment significantly attenuated the severity of intestinal I/R injury. Furthermore, there is a significant reduction in the activity of inducible nitric oxide synthase and increase in the expression of surfactant protein D in lung tissue of acute lung injury induced by intestinal I/R with curcumin therapy. It was concluded that curcumin treatment may have beneficial effects in acute lung injury, and therefore has potential for clinical use.

Respiratory Effects of Traffic-Related Air Pollution: A Randomized, Crossover Analysis of Lung Function, Airway Metabolome, and Biomarkers of Airway Injury.

BACKGROUND: Exposure to traffic-related air pollution (TRAP) has been associated with increased risks of respiratory diseases, but the biological mechanisms are not yet fully elucidated. OBJECTIVES: Our aim was to evaluate the respiratory responses and explore potential biological mechanisms of TRAP exposure in a randomized crossover trial. METHODS: We conducted a randomized crossover trial in 56 healthy adults. Each participant was exposed to high- and low-TRAP exposure sessions by walking in a park and down a road with high traffic volume for 4 h in random order. Respiratory symptoms and lung function, including forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), the ratio of FEV1 to FVC, and maximal mid-expiratory flow (MMEF), were measured before and after each exposure session. Markers of 8-isoprostane, tumor necrosis factor-α (TNF-α), and ezrin in exhaled breath condensate (EBC), and surfactant proteins D (SP-D) in serum were also measured. We used linear mixed-effects models to estimate the associations, adjusted for age, sex, body mass index, meteorological condition, and batch (only for biomarkers). Liquid chromatography-mass spectrometry was used to profile the EBC metabolome. Untargeted metabolome-wide association study (MWAS) analysis and pathway enrichment analysis using mummichog were performed to identify critical metabolomic features and pathways associated with TRAP exposure. RESULTS: Participants had two to three times higher exposure to traffic-related air pollutants except for fine particulate matter while walking along the road compared with in the park. Compared with the low-TRAP exposure at the park, high-TRAP exposure at the road was associated with a higher score of respiratory symptoms [2.615 (95% CI: 0.605, 4.626), p=1.2×10-2] and relatively lower lung function indicators [-0.075L (95% CI: -0.138, -0.012), p=2.1×10-2] for FEV1 and -0.190L/s (95% CI: -0.351, -0.029; p=2.4×10-2) for MMEF]. Exposure to TRAP was significantly associated with changes in some, but not all, biomarkers, particularly with a 0.494-ng/mL (95% CI: 0.297, 0.691; p=9.5×10-6) increase for serum SP-D and a 0.123-ng/mL (95% CI: -0.208, -0.037; p=7.2×10-3) decrease for EBC ezrin. Untargeted MWAS analysis revealed that elevated TRAP exposure was significantly associated with perturbations in 23 and 32 metabolic pathways under positive- and negative-ion modes, respectively. These pathways were most related to inflammatory response, oxidative stress, and energy use metabolism. CONCLUSIONS: This study suggests that TRAP exposure might lead to lung function impairment and respiratory symptoms. Possible underlying mechanisms include lung epithelial injury, inflammation, oxidative stress, and energy metabolism disorders. https://doi.org/10.1289/EHP11139.

Ozone-induced lung injury and sterile inflammation. Role of toll-like receptor 4.

Inhalation of toxic doses of ozone is associated with a sterile inflammatory response characterized by an accumulation of macrophages in the lower lung which are activated to release cytotoxic/proinflammatory mediators that contribute to tissue injury. Toll-like receptor 4 (TLR4) is a pattern recognition receptor present on macrophages that has been implicated in sterile inflammatory responses. In the present studies we used TLR4 mutant C3H/HeJ mice to analyze the role of TLR4 in ozone-induced lung injury, oxidative stress and inflammation. Acute exposure of control C3H/HeOuJ mice to ozone (0.8ppm for 3h) resulted in increases in bronchoalveolar lavage (BAL) lipocalin 24p3 and 4-hydroxynonenal modified protein, markers of oxidative stress and lipid peroxidation. This was correlated with increases in BAL protein, as well as numbers of alveolar macrophages. Levels of surfactant protein-D, a pulmonary collectin known to regulate macrophage inflammatory responses, also increased in BAL following ozone inhalation. Ozone inhalation was associated with classical macrophage activation, as measured by increased NF-κB binding activity and expression of TNFα mRNA. The observation that these responses to ozone were not evident in TLR4 mutant C3H/HeJ mice demonstrates that functional TLR4 contributes to ozone-induced sterile inflammation and macrophage activation.

Complex Evaluation of Surfactant Protein A and D as Biomarkers for the Severity of COPD.

Purpose: Pulmonary surfactant proteins A (SP-A) and D (SP-D) are lectins, involved in host defense and regulation of pulmonary inflammatory response. However, studies on the assessment of COPD progress are limited. Patients and Methods: Pulmonary surfactant proteins were obtained from the COPD mouse model induced by cigarette and lipopolysaccharide, and the specimens of peripheral blood and bronchoalveolar lavage (BALF) in COPD populations. H&E staining and RT-PCR were performed to demonstrate the successfully established of the mouse model. The expression of SP-A and SP-D in mice was detected by Western Blot and immunohistochemistry, while the proteins in human samples were measured by ELISA. Pulmonary function test, inflammatory factors (CRP, WBC, NLR, PCT, EOS, PLT), dyspnea index score (mMRC and CAT), length of hospital stay, incidence of complications and ventilator use were collected to assess airway remodeling and progression of COPD. Results: COPD model mice with emphysema and airway wall thickening were more prone to have decreased SP-A, SP-D and increased TNF-α, TGF-ß, and NF-kb in lung tissue. In humans, SP-A and SP-D decreased in BALF, but increased in serum. The serum SP-A and SP-D were negatively correlated with FVC, FEV1, FEV1/FVC, and positively correlated with CRP, WBC, NLR, mMRC and CAT scores (P < 0.05, respectively). The lower the SP-A and SP-D in BALF, the worse the lung function and the increased probability of complications and ventilator use. Moreover, the same trend emerged in COPD patients grouped according to GOLD severity grade (Gold 1-2 group vs Gold 3-4 group). The worse the patient's condition, the more pronounced the change. Conclusion: This study suggests that SP-A and SP-D may be related to the progression and prognostic evaluation of COPD in terms of airway remodeling, inflammatory response and clinical symptoms, and emphasizes the necessity of future studies of surfactant protein markers in COPD.

Biomarkers of early respiratory effects in smoking adolescents.

Noninvasive biomarkers can be used to evaluate airways damage caused by tobacco smoke, but studies so far have only involved adult smokers. In this study, we evaluated whether such biomarkers can detect early respiratory effects in adolescents passively or actively exposed to tobacco smoke. In a cross-sectional study of 845 adolescents (mean age 16 yrs), we measured exhaled nitric oxide (NO) and various epithelial markers in nasal lavage fluid (NALF) and serum, including Clara cell protein (CC16) and surfactant protein (SP)-D. Information about smoking habits and potential confounders was collected by questionnaire. Four groups of equal size (n = 36), of nonsmokers, passive smokers, light smokers (<5 cigarettes · day(-1), median 0.08 pack-yrs) and heavy smokers (≥ 5 cigarettes · day(-1), median 0.35 pack-yrs), were matched using an automated procedure. The levels of exhaled NO and of CC16 in NALF were significantly decreased in the group of heavy smokers. A trend towards lower levels of CC16 in NALF was observed in passive smokers. There were no significant changes in serum CC16 and SP-D, which suggests that the deep lung epithelium had not yet been affected by smoking. In conclusion, tobacco smoke can cause early changes in the airways of adolescents with a cumulative smoking history of <1 pack-yr.

Plasminogen activation inhibitor concentrations in bronchoalveolar lavage fluid distinguishes ventilator-associated pneumonia from colonization in mechanically ventilated pediatric patients.

OBJECTIVE: To compare the ability of four biomarkers to distinguish between those with ventilator-associated pneumonia (VAP) vs. lower respiratory tract bacterial colonization in mechanically ventilated intensive care unit (ICU) pediatric patients. DESIGN: Prospective, pilot cohort study. SETTING: Tertiary care children's hospital, pediatric ICU. PATIENTS: All pediatric ICU patients mechanically ventilated > 48 hrs were eligible for enrollment between April 2006 to May 2007. Thirty-three patients were consecutively screened and enrolled after institutional consent process. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: VAP was defined by both Centers for Disease and Prevention/National Nosocomial Infections Surveillance criteria and clinician diagnosis; those not meeting the criteria were considered to be colonized. Plasminogen activation inhibitor (PAI-1), soluble triggering receptor expressed on myeloid cells, receptor for advanced glycation end-products, and surfactant protein D levels were measured in bronchoalveolar lavage samples on average within 24 hrs of suspicion for VAP, i.e., a positive screening endotracheal Gram stain. Sixteen patients were diagnosed with VAP and 17 met the criteria for colonization. PAI-1 was associated with VAP independent of age, sex, race, acute lung injury/acute respiratory distress syndrome, Pediatric Risk of Mortality 3 score, pediatric logistic organ dysfunction score, and duration of intubation. The receiver operating characteristics for PAI-1 showed good discrimination with an area under the curve of 0.82. PAI-1 levels of ≥ 2.8 ng/mL had a sensitivity of 81.3%, specificity of 76.5%, and positive likelihood ratio of 3.5. Levels of soluble triggering receptor expressed on myeloid cells, receptor for advanced glycation end-products, and surfactant protein D were not significantly associated with VAP. CONCLUSIONS: In mechanically ventilated pediatric ICU patients, PAI-1 is independently associated with the diagnosis of VAP. Real-time measurement of PAI-1 levels in bronchoalveolar lavage fluid may be of benefit in the early diagnosis and subsequent treatment of VAP in ICU patients.

Levels of surfactant proteins A and D and KL-6 are elevated in the induced sputum of chronic obstructive pulmonary disease patients: a sequential sputum analysis.

BACKGROUND: Recent clinical studies have suggested that serum surfactant protein (SP) A, SP-D and Krebs von den Lungen-6 (KL-6) are potential biomarkers for interstitial lung diseases. Serum levels of SP-A and SP-D have also been found to be elevated in chronic obstructive pulmonary disease (COPD), but their significance has not been evaluated or compared in induced sputum samples obtained directly from the airways. OBJECTIVE: A sequential sputum analysis was conducted to assess the value of SP-A, SP-D and KL-6 levels in COPD. METHODS: The study material consisted of induced sputum samples from 61 subjects, 28 with COPD and 33 with prolonged cough (cough lasting >3 weeks and normal spirometry). Sputum was collected in 3 fractions (3 periods of 5 min each). Sputum levels of these proteins were measured, and receiver operating characteristic curve analysis was carried out to evaluate the sensitivity, specificity and area under the curve (AUC) for each fraction. RESULTS: The levels of SP-A, SP-D and KL-6 were higher in patients with COPD than in those with prolonged cough in each of the fractions. Sputum levels of these proteins correlated inversely with obstruction and positively with ageing, smoking history, sputum macrophages and eosinophils. Sputum fractionation had a relatively minor effect on the levels and AUC of these proteins. CONCLUSION: Sequential sputum analysis from 3 consecutive fractions indicated a significant difference in the levels of SP-A, SP-D and KL-6 between COPD and prolonged cough. However, sputum fractionation itself had a relatively minor effect on the levels of these proteins.

Development of an enzyme-linked immunosorbent assay for measurement of rat pulmonary surfactant protein D using monoclonal antibodies.

Surfactant protein D (SP-D) has been used as a biomarker of lung inflammation. In rat, several types of enzyme-linked immunosorbent assay (ELISA) using polyclonal antibodies have been reported. The purpose of this study was the development of a sensitive ELISA for rat SP-D using monoclonal antibodies. The authors developed a sandwich ELISA using monoclonal antibodies that were obtained by immunizing with purified rat SP-D. The ELISA was evaluated by performance tests. Furthermore, concentrations of serum SP-D were measured in normal control and bleomycin-treated rats. The working range of ELISA was between 0.47 and 30 ng/mL. Different concentrations of added SP-D were recovered, between 94.1% and 102.8%. Serum SP-D levels of bleomycin-treated rats were significantly higher than those of normal rats. In conclusion, this newly developed ELISA for rat SP-D using monoclonal antibodies is applicable for research on the mechanism and therapy of lung injury.

Smoking reduces surfactant protein D and phospholipids in patients with and without chronic obstructive pulmonary disease.

BACKGROUND: Pulmonary surfactant D (SP-D) has important regulatory functions for innate immunity and has been implicated as a biomarker for chronic obstructive pulmonary disease (COPD). We hypothesized that COPD patients would have reduced bronchoalveolar lavage (BAL) fluid SP-D levels compared to healthy smoking and non-smoking controls. METHODS: BAL SP-D and phospholipids were quantified and corrected for dilution in 110 subjects (65 healthy never smokers, 23 smokers with normal spirometry, and 22 smokers with COPD). RESULTS: BAL SP-D was highest in never smokers (mean 51.9 µg/mL ± 7.1 µg/mL standard error) compared to both smokers with normal spirometry (16.0 µg/mL ± 11.8 µg/mL) and subjects with COPD (19.1 µg/mL ± 12.9 µg/mL; P < 0.0001). Among smokers with COPD, BAL SP-D correlated significantly with FEV1% predicted (R = 0.43; P < 0.05); however, the strongest predictor of BAL SP-D was smoking status. BAL SP-D levels were lowest in current smokers (12.8 µg/mL ± 11.0 µg/mL), intermediate in former smokers (25.2 µg/mL ± 14.2 µg/mL; P < 0.008), and highest in never smokers. BAL phospholipids were also lowest in current smokers (6.5 nmol ± 1.5 nmol), intermediate in former smokers (13.1 nmol ± 2.1 nmol), and highest in never smokers (14.8 nmol ± 1.1 nmol; P < 0.0001). CONCLUSIONS: These data suggest that smokers, and especially current smokers, exhibit significantly reduced BAL SP-D and phospholipids compared to nonsmokers. Our findings may help better explain the mechanism that leads to the rapid progression of disease and increased incidence of infection in smokers.