New bronchoscopic microsample probe to measure the biochemical constituents in epithelial lining fluid of patients with acute respiratory distress syndrome

Vascular endothelial growth factor in epithelial lining fluid of patients with acute respiratory distress syndrome

BACKGROUND AND OBJECTIVE

Vascular endothelial growth factor (VEGF) is known to contribute to the development of pulmonary oedema, and has been suggested to have a protective role against lung injury. To determine the role of VEGF in acute lung injury (ALI) and ARDS, VEGF levels were measured in lung epithelial lining fluid (ELF) collected from patients with ALI/ARDS.

METHODS

Forty patients with ALI/ARDS underwent bronchoscopic microsampling to collect ELF on days 0 (onset of ALI/ARDS), 1, 3, 5, 7 and 10, unless the patient was extubated or had died. Twelve patients, who underwent bronchoscopy for examination of small, peripheral pulmonary nodules, served as controls.

RESULTS

The initial (day 0) levels of VEGF in ELF of the ALI/ARDS patients who survived and those who did not were 5.5 ng/mL (IQR: 2.3-19.7) and 1.7 ng/mL (IQR: 0.0-6.4), respectively. On days 0, 5, 7 and 10, the VEGF levels in ELF were significantly greater in survivors than in non-survivors (P < 0.05). VEGF levels on days 1 and 3 did not differ between survivors and non-survivors. There was no significant difference in ELF VEGF levels between control subjects and patients with ALI/ARDS at any time point. Lung injury score was inversely correlated with VEGF concentration in ELF (P < 0.001).

CONCLUSIONS

In patients with ALI/ARDS, elevated VEGF levels in ELF may predict a better outcome. Increased production of VEGF in the injured lung may contribute to resolution of inflammation in the lung.

Dual oxidase 1 and 2 expression in airway epithelium of smokers and patients with mild/moderate chronic obstructive pulmonary disease

Dual oxidase (Duox) 1 and Duox2 are important sources of hydrogen peroxide production and play a role in host defense in airways. Little is known about their regulation in association with smoking or chronic obstructive pulmonary disease (COPD). We investigated the epithelial expression of Duox1 and Duox2 in the airways of smokers, and the relationship between this expression and COPD at early stage. First, using bronchoscopy, we harvested tracheal and bronchial epithelium from individuals who have never smoked and current smokers. Duox1 expression in brushed tracheal and bronchial epithelium was significantly downregulated, whereas Duox2 was upregulated, in current smokers as compared to individuals who have never smoked. Second, laser capture microdissection and microscope-assisted manual dissection were performed in surgically resected lung tissues to collect bronchiolar epithelium and alveolar septa. Subjects with mild/moderate COPD, who were all former smokers, exhibited downregulation of bronchiolar Duox1 and Duox2 when compared to individuals who have never smoked, whereas a difference between former smokers, with and without COPD, was observed only for Duox1. Alveolar Duox1 and Duox2 expression was low and did not differ among the groups. These results imply that the airway expression of Duox1 and Duox2 is diversely associated with smoking and COPD.

Dexamethasone therapy in preterm infants developing bronchopulmonary dysplasia: effect on pulmonary surfactant disaturated-phosphatidylcholine kinetics

The role of corticosteroid in severe bronchopulmonary dyplasia (BPD) is still debated. Scanty data are available on the corticosteroids effect on surfactant metabolism. Our objective was to compare surfactant kinetics in preterm infants with developing BPD, before and after dexamethasone (DEXA) treatment. Twenty-eight studies were performed in 14 preterm infants (birth weight 786 +/- 192 g, gestational age 26 +/- 1 wk) on high ventilatory setting, before (age 22 +/- 11 d) and after (age 33 +/- 11 d) DEXA. C-labeled dipalmitoyl-phosphatidylcholine (DPPC) was administered endotrachelly to trace pulmonary surfactant. Surfactant disaturated-phosphatidylcholine (DSPC) kinetics and pools were calculated from DSPC C-enrichment curves of serial tracheal aspirates and bi-compartmental analysis. Total protein and myeloperoxidase (MPO) activity in tracheal aspirates were also measured and expressed per ml of Epithelial Lining Fluid (ELF). After DEXA, DSPC alveolar pool increased significantly from 8.2 +/- 7.6 to 10.6 +/- 11.3 mg/kg (p = 0.039), total proteins and MPO were reduced from 8.8 +/- 8.6 to 3.1 +/- 2.1 mg/ml ELF (p = 0.046) and from 1822 +/- 1224 to 1261 +/- 987 mU/mlELF (p = 0.028) respectively. In conclusion, DEXA treatment in mechanically ventilated preterm infants with severe respiratory failure and at high risk of developing BPD, significantly reduced inflammatory markers and increased alveolar surfactant DSPC pool.

Endothelin-1 level in epithelial lining fluid of patients with acute respiratory distress syndrome

BACKGROUND AND OBJECTIVES

Endothelin-1 (ET-1), a potent vasoconstrictor peptide produced by endothelial cells, has been implicated in the dysfunction of various organs. To determine the role of ET-1 in acute lung injury (ALI) and ARDS, ET-1 levels were measured in epithelial lining fluid (ELF) and plasma obtained from patients with ALI/ARDS.

METHODS

A cross-sectional study of patients with ALI/ARDS in the intensive care unit of two university hospitals was performed. Patients with ALI/ARDS underwent bronchoscopic microsampling to collect ELF on the day of onset of the disease. Patients who underwent bronchoscopy to examine a small peripheral pulmonary nodule served as controls.

RESULTS

In the 23 patients with ALI/ARDS, the ET-1 level in ELF was significantly greater than that in plasma (P < 0.001). In contrast, ET-1 was not detectable in the ELF from six of the seven control subjects. The albumin concentration of ELF, used as a marker of endothelial and epithelial permeability, correlated with the ET-1 level in ELF (P < 0.001). The oxygenation index (PaO(2)/FiO(2)) was also correlated with ET-1 concentration in ELF (P < 0.001).

CONCLUSION

In patients with ALI/ARDS, ET-1 is produced mainly in the lung and is associated not only with pulmonary vasoconstriction but also the development of permeability oedema, leading to the impairment of oxygenation.

Pharmacokinetics of gatifloxacin after a single oral dose in healthy young adult subjects and adult patients with chronic bronchitis, with a comparison of drug concentrations obtained by bronchoscopic microsampling and bronchoalveolar lavage

BACKGROUND

Bronchoalveolar lavage (BAL) is an established technique for measuring antibiotic concentrations in the epithelial lining fluid (ELF) of the bronchiolar and alveolar regions; however, the results may not reflect concentrations in bronchial regions. Bronchoscopic microsampling (BMS) is a technique that makes it possible to obtain multiple samples from bronchial ELF.

OBJECTIVE

BMS and BAL were used to analyze the pharmacokinetics of gatifloxacin in bronchial ELF from healthy young adult subjects and adult patients with chronic bronchitis.

METHODS

Bronchial ELF samples were obtained by BMS at 1, 2, 3, 4, 6, 10, and 24 hours after administration of a single oral dose of gatifloxacin 200 mg in healthy young adult (aged 20-25 years) subjects, and at 1, 2, 4, and 10 hours after a single dose in patients with chronic bronchitis (aged > or =20 years). At least 1 month after the initial BMS, alveolar (BAL) and bronchial (BMS) ELF samples were obtained from another group of healthy subjects 2 hours after administration of a single oral dose of gatifloxacin 200 mg for comparison of gatifloxacin concentrations in samples obtained by the 2 techniques.

RESULTS

Bronchial ELF samples were obtained from 8 healthy subjects and 5 patients with chronic bronchitis; alveolar ELF samples were obtained from a separate group of 5 healthy subjects. For the healthy subjects, the mean (SD) AUC(0-24) in serum and bronchial ELF, corrected for mg/kg doses, was 4.6 (1.1) and 7.6 (3.5) mg x h/L, respectively. In the patients with chronic bronchitis, the AUC(0-10) in serum and bronchial ELF, corrected for mg/kg doses, was 3.9 (0.8) and 4.1 (1.5) mg x h/L. The C(max) in serum and bronchial ELF, corrected for mg/kg doses, was 0.6 (0.2) and 1.4 (0.8) mg/L in healthy subjects and 0.7 (0.2) and 0.7 (0.2) mg/L in patients with chronic bronchitis. In healthy subjects, the C(max) and AUC(0-24) were significantly higher in bronchial ELF than in serum (both, P < 0.05). Gatifloxacin concentrations were significantly lower in bronchial ELF obtained by BMS than in alveolar ELF obtained by BAL (P < 0.05).

CONCLUSIONS

Based on the findings of this study in small numbers of healthy young adult volunteers and patients with chronic bronchitis, BMS appears to be a promising method for measuring drug concentrations and determining the pharmacokinetic profile of gatifloxacin in bronchial ELF. Additional studies are needed to correlate measured concentrations obtained by BMS with clinical and/or microbiologic outcomes in larger populations.

Usefulness of bronchoscopic microsampling to detect the pathogenic bacteria of respiratory infection

BACKGROUND

Bronchoscopic microsampling (BMS) is a method in which a device consisting of a wire with a polyester probe at the tip is used to collect bronchial epithelial lining fluid with bronchoscopy. In this study, we bacteriologically investigated sample collection using BMS to incorporate BMS into diagnosis of respiratory infection.

METHODS

Strains of Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa, and Mycobacterium avium complex (MAC), were used for experiments. In the standard sampling procedure using BMS, the probe coming out of the sheath was immersed in approximately 6 x 10(6) cfu/mL bacterial suspension for 30 s and cut into a tube containing 1 mL of normal saline solution. The tube was stirred for 1 min using a vortex. The sampling rate was calculated by the following equation: (actual amount of bacteria collected by BMS [colony forming units per milliliter])/(bacterial amount in suspension for sampling [colony forming units per milliliter]) x 100 (percentage).

RESULTS

The sampling rate of S pneumoniae, H influenzae, and MAC showed no significant difference among three bacteria, but the sampling rate of P aeruginosa was higher. The shortened time of sampling, stirring, and the reduced bacterial amount in the suspension (1/100) did not significantly affect the rates of standard procedure. In contrast, in comparison with a protected specimen brush (PSB), the recoveries of S pneumoniae, H influenzae, and MAC using PSB were significantly lower than those by BMS, but the recovery of P aeruginosa was not significantly different.

CONCLUSION

This in vitro study might suggested the usefulness of BMS as a new diagnostic technique capable of quantitative and stable sampling.

Significance of human β-defensins in the epithelial lining fluid of patients with chronic lower respiratory tract infections

Human beta-defensins (hBDs) are the most abundant antimicrobial peptides in epithelial cells, and function in the host immune system. Respiratory epithelial cells express hBDs to inhibit bacterial proliferation during respiratory tract infections. The aim of this study was to investigate the release of hBDs into the respiratory tract and their benefit as a host defence system in chronic Pseudomonas aeruginosa infections. The levels of four hBD peptides (hBD-1-hBD-4) were measured in the bronchial epithelial lining fluid (ELF) of nine patients with chronic lower respiratory tract infection caused by P. aeruginosa. Eight patients with idiopathic pulmonary fibrosis and eight volunteers free of pulmonary disease were recruited as controls. ELF was obtained by bronchoscopic microsampling and hBD levels were measured by radioimmunoassays. The antimicrobial effects of hBDs were studied individually and in combination using an in-vitro colony count assay for P. aeruginosa. Concentrations of hBD-1 and hBD-3 tended to be higher in patients with chronic lower respiratory tract infection than in the controls. hBD-2 and hBD-4 were detected in ELF from five and four of nine patients, respectively, but the hBD levels in controls were all below the limits of detection. All patients with infection caused by mucoid P. aeruginosa had detectable hBD-2 and hBD-4 levels in ELF. In-vitro colony count assays showed a potential synergism between hBD-2 and hBD-4 in inhibiting bacterial proliferation. The findings indicate that hBDs, especially hBD-2 and hBD-4, are pathophysiologically important in infections caused by mucoid strains of P. aeruginosa.

Activation of a Neutrophil-Derived Inflammatory Response in the Airways During Cardiopulmonary Bypass

Cardiopulmonary bypass (CPB) is believed to cause postoperative lung dysfunction. To more closely examine the inflammatory processes occurring in the airways during CPB, we serially measured inflammatory mediators, with the assistance of a new bronchoscopic microsample probe, in 11 patients undergoing repair of aortic arch aneurysms. Epithelial lining fluid (ELF) and arterial blood were sampled simultaneously after induction of anesthesia, at the time of pulmonary reperfusion, and at the end of surgery. A decrease in the PaO2/FiO2 ratio was observed at the end of surgery (P = 0.029). Although the ELF concentrations of interleukin (IL)-8, IL-6, and neutrophil elastase had increased significantly at the end of surgery (median = 23,200, 1818, and 12,900 microg/mL, respectively), they did not correlate with the degree of hypoxemia. Neutrophil elastase increased significantly at the time of pulmonary reperfusion, before IL-8 and IL-6, and independently of blood transfusions. At the end of surgery, IL-6 in ELF correlated with total blood transfusion volume (rho = 0.731, P = 0.011). These results indicate that a neutrophil-derived inflammatory response is activated in the airway in the early phase of CPB.

Proteomics in pulmonary medicine

Proteomics is the study of the entire protein complement of the genome (the proteome) in a biological system. Proteomic studies require a multidisciplinary approach and have only been practical with the convergence of technical and methodologic improvements including the following: advances in mass spectrometry and genomic sequencing that now permit the identification and relative quantization of small amounts (femtomole) of nearly any single protein; new methods in gel electrophoresis that allow the detection of subtle changes in protein expression, including posttranslational modifications; automation and miniaturization that permit high-throughput analysis of clinical samples; and new bioinformatics and computational methods that facilitate analysis and interpretation of the abundant data that are generated by proteomics experiments. This convergence makes proteomics studies practical for pulmonary researchers using BAL fluid, lung tissue, blood, and exhaled breath condensates, and will facilitate the research of complex, multifactorial lung diseases such as acute lung injury and COPD. This review describes how proteomics experiments are conducted and interpreted, their limitations, and how proteomics has been used in clinical pulmonary medicine.

Pharmacokinetics of telithromycin using bronchoscopic microsampling after single and multiple oral doses

OBJECTIVES

Bronchoscopic microsampling (BMS) is a new technique for repeated sampling of bronchial epithelial lining fluid (ELF) to obtain the pharmacokinetic profile of drugs. We analyzed the time versus concentration profiles of telithromycin in bronchial ELF obtained by BMS and compared these finding to those in plasma and alveolar ELF obtained by bronchoalveolar lavage (BAL).

METHODS

Bronchial ELF samples were obtained from five healthy subjects using BMS probe at 0, 2, 3, 4, 6, 10 and 24h after single or multiple oral doses of 600 mg of telithromycin. Alveolar ELF was also obtained by BAL 3h after single or multiple oral doses of 600 mg of telithromycin.

RESULTS

The areas under the concentration-time curve from 0 to 24h (AUC0-24) of telithromycin in plasma and bronchial ELF were 2.86+/-0.60 and 19.5+/-10.4 mg h/l after single treatment and 3.60+/-0.49 and 42.2+/-22.7 mg h/l after multiple treatments, respectively. Single and multiple oral doses of telithromycin produced significantly (p<0.05) higher AUC0-24 in bronchial ELF compared to those in plasma. While concentrations in bronchial ELF obtained by BMS were significantly lower than those in alveolar ELF obtained by BAL, they tended to be higher than those in plasma after multiple administration. The telithromycin concentrations obtained by BMS method were very consistent in bronchial ELF at different bronchi at one time point and at the same bronchus at different time points.

CONCLUSIONS

Using the BMS technique, we could describe the pharmacokinetics of telithromycin in bronchial ELF. Furthermore, BMS was reasonably validated and reconfirmed to be a feasible and reliable method for measuring antimicrobial concentrations in bronchial ELF.

Cytokine-mediated xanthine oxidase upregulation in chronic obstructive pulmonary disease's airways

Reactive oxygen species have been reported to be involved in the airway inflammatory process of chronic obstructive pulmonary disease (COPD). The aim of this study was to quantify the activity of xanthine oxidase (XO), which generates a potent radical superoxide anion in COPD airways. Thirteen stable COPD patients and 10 healthy subjects participated in this study. We collected the epithelial lining fluid using a newly developed microsampling technique, and quantified of cytokines responsible for the XO gene upregulation. The XO activity was significantly increased in COPD patients compared with that in healthy subjects. A significant negative correlation was found between the XO activity and the %FEV1 values. The level of tumor necrosis factor-alpha, interleukin-1beta, and interferon-gamma in COPD patients was significantly higher than that in healthy subjects. Both the amount of tumor necrosis factor-alpha and interleukin-1beta were significantly correlated with the degree of XO activity. These results suggest that the XO activity is increased in COPD airways, possibly due to its gene upregulation by proinflammatory cytokines. Because the XO activity was significantly correlated with the degree of airway obstruction, these cytokine-XO production pathways may play a key role in the inflammation of COPD.

Bronchoscopic assessment of airway retention time of aerosolized xylitol

Background

Human airway surface liquid (ASL) has abundant antimicrobial peptides whose potency increases as the salt concentration decreases. Xylitol is a 5-carbon sugar that has the ability to lower ASL salt concentration, potentially enhancing innate immunity. Xylitol was detected for 8 hours in the ASL after application in airway epithelium in vitro. We tested the airway retention time of aerosolized iso-osmotic xylitol in healthy volunteers.

Methods

After a screening spirometry, volunteers received 10 ml of nebulized 5% xylitol. Bronchoscopy was done at 20 minutes (n = 6), 90 minutes (n = 6), and 3 hours (n = 5) after nebulization and ASL was collected using microsampling probes, followed by bronchoalveolar lavage (BAL). Xylitol concentration was measured by nuclear magnetic resonance spectroscopy and corrected for dilution using urea concentration.

Results

All subjects tolerated nebulization and bronchoscopy well. Mean ASL volume recovered from the probes was 49 ± 23 μl. The mean ASL xylitol concentration at 20, 90, and 180 minutes was 1.6 ± 1.9 μg/μl, 0.6 ± 0.6 μg/μl, and 0.1 ± 0.1 μg/μl, respectively. Corresponding BAL concentration corrected for dilution was consistently lower at all time points. The terminal half-life of aerosolized xylitol obtained by the probes was 45 minutes with a mean residence time of 65 minutes in ASL. Corresponding BAL values were 36 and 50 minutes, respectively.

Conclusion

After a single dose nebulization, xylitol was detected in ASL for 3 hours, which was shorter than our in vitro measurement. The microsampling probe performed superior to BAL when sampling bronchial ASL.

Role of nonbronchoscopic lavage for investigating alveolar inflammation and permeability in acute respiratory distress syndrome

OBJECTIVE

Nonbronchoscopic bronchoalveolar lavage is often used as an alternative to bronchoscopic bronchoalveolar lavage in the diagnosis of ventilator-associated pneumonia. We have previously reported an improved safety profile for nonbronchoscopic lavage in patients with lung injury, suggesting that this may be a better technique in this patient group. The objective of this study was to determine whether nonbronchoscopic lavage could be used as an alternative to bronchoscopic lavage for the assessment of alveolar permeability and inflammation in patients at risk for acute respiratory distress syndrome (ARDS) or with ARDS.

DESIGN

Prospective randomized crossover trial.

PATIENTS

Intubated patients with ARDS or at risk of ARDS.

INTERVENTIONS

Bronchoscopic and nonbronchoscopic lavage in the same patient, 15 mins apart.

MEASUREMENTS AND MAIN RESULTS

Twenty-one patients with ARDS and 20 patients at risk of ARDS were recruited and underwent nonbronchoscopic and bronchoscopic lavage in randomized order. Despite similar volumes of lavage fluid, nonbronchoscopic lavage had fewer cells and an increased ratio of bronchial epithelial cells to macrophages. Although average concentrations of myeloperoxidase and total protein, the protein permeability index, and the epithelial-lining fluid volume were similar with the two techniques and demonstrated moderate linear associations, Bland and Altman analysis revealed poor comparability, with substantial side-to-side variability and wide 95% limits of agreement. Furthermore, unlike bronchoscopic lavage, nonbronchoscopic lavage was unable to differentiate between patients with ARDS and those at risk of ARDS.

CONCLUSIONS

Nonbronchoscopic lavage is not comparable to bronchoscopic lavage and as such cannot be used as an alternative to bronchoscopic lavage for assessing alveolar inflammation in patients with ARDS.

Isolation of human beta-defensin-4 in lung tissue and its increase in lower respiratory tract infection

BACKGROUND

Human beta-defensin-4 (hBD-4), a new member of the beta-defensin family, was discovered by an analysis of the genomic sequence. The objective of this study was to clarify hBD-4 expression in human lung tissue, along with the inducible expression in response to infectious stimuli, localization, and antimicrobial activities of hBD-4 peptides. We also investigated the participation of hBD-4 in chronic lower respiratory tract infections (LRTI) by measuring the concentrations of hBD-4 peptides in human bronchial epithelial lining fluid (ELF).

METHODS

The antimicrobial activity of synthetic hBD-4 peptides against E. coli and P. aeruginosa was measured by radial diffusion and colony count assays. We identified hBD-4 in homogenated human lung tissue by reverse-phase high-performance liquid chromatography coupled with a radioimmunoassay (RIA). Localization of hBD-4 was studied through immunohistochemical analysis (IHC). We investigated the effects of lipopolysaccharide (LPS) on hBD-4 expression and its release from small airway epithelial cells (SAEC). We collected ELF from patients with chronic LRTI using bronchoscopic microsampling to measure hBD-4 concentrations by RIA.

RESULTS

hBD-4 exhibited salt-sensitive antimicrobial activity against P. aeruginosa. We detected the presence of hBD-4 peptides in human lung tissue. IHC demonstrated the localization of hBD-4-producing cells in bronchial and bronchiolar epithelium. The levels of hBD-4 peptides released from LPS-treated SAECs were higher than those of untreated control cells. ELF hBD-4 was detectable in 4 of 6 patients with chronic LRTI, while the amounts in controls were all below the detectable level.

CONCLUSION

This study suggested that hBD-4 plays a significant role in the innate immunity of the lower respiratory tract.

Contributions of high mobility group box protein in experimental and clinical acute lung injury

This study was performed to examine the putative role of high mobility group box (HMGB) protein in the pathogenesis of acute lung injury (ALI). Observations were made (1) in 21 patients who were septic with ALI and 15 patients with normal lung function and (2) in a mouse model 24 hours after intratracheal instillation of lipopolysaccharide (LPS). The concentrations of HMGB1 were increased in plasma and lung epithelial lining fluid of patients with ALI and mice instilled with LPS. LPS-induced ALI was mitigated by anti-HMGB1 antibody. Although this protein was not detected in the plasma of control humans or mice, the concentrations of HMGB1 in lung epithelial lining fluid or in bronchoalveolar lavage fluid were unexpectedly high. The nuclear expression of HMGB1 was apparent in epithelial cells surrounding terminal bronchioles in normal mice, whereas its nuclear and cytoplasmic expression was observed in alveolar macrophages in LPS-instilled mice. Lung instillation of HMGB2 did not cause as much inflammation as HMGB1. Extracellular HMGB1 may play a key role in the pathogenesis of clinical and experimental ALI. However, its expression in normal airways is noteworthy and suggests that it also plays a physiologic role in the lung.

Elevation of KL-6, a lung epithelial cell marker, in plasma and epithelial lining fluid in acute respiratory distress syndrome

KL-6 is a pulmonary epithelial mucin more prominently expressed on the surface membrane of alveolar type II cells when these cells are proliferating, stimulated, and/or injured. We hypothesized that high levels of KL-6 in epithelial lining fluid and plasma would reflect the severity of lung injury in patients with acute lung injury (ALI). Epithelial lining fluid was obtained at onset (day 0) and day 1 of acute respiratory distress syndrome (ARDS)/ALI by bronchoscopic microsampling procedure in 35 patients. On day 0, KL-6 and albumin concentrations in epithelial lining fluid were significantly higher than in normal controls (P < 0.001), and the concentrations of KL-6 in epithelial lining fluid (P < 0.002) and in plasma (P < 0.0001) were higher in nonsurvivors than in survivors of ALI/ARDS. These observations were corroborated by the immunohistochemical localization of KL-6 protein expression in the lungs of nonsurvivors with ALI and KL-6 secretion from cultured human alveolar type II cells stimulated by proinflammatory cytokines. Because injury to distal lung epithelial cells, including alveolar type II cells, is important in the pathogenesis of ALI, the elevation of KL-6 concentrations in plasma and epithelial lining fluid could be valuable indicators for poor prognosis in clinical ALI.

Bronchoscopic microsampling method for measuring drug concentration in epithelial lining fluid

Direct measurement of the concentration of antimicrobial agents in bronchial epithelial lining fluid (ELF) would allow for a more informed approach to appropriate dosing of antimicrobial agents for respiratory tract infections. In this study, we determined the time versus concentration profile in ELF after an oral administration of levofloxacin, using recently developed bronchoscopic microsampling probes. These probes could be repeatedly and safely inserted through the fiberoptic bronchoscope in normal healthy volunteers. The concentration of levofloxacin in ELF was 43.4% of the corresponding serum value at 1 hour, reached the same level at 2 hours, decreased in a similar manner as that in serum, and returned to undetectable levels at 24 hours. It exceeded minimal inhibitory concentrations of Staphylococcus aureus (0.25 microg/ml), Klebsiella species (0.5 microg/ml), and Haemophilus influenzae (0.06 microg/ml) after 6 hours. The experimental procedure was well tolerated, and no complications were observed. In conclusion, bronchoscopic microsampling is a feasible and promising method for measuring antimicrobial concentrations in the target sites of respiratory tracts directly and repeatedly.

Contributions of bronchoscopic microsampling in the supplemental diagnosis of small peripheral lung carcinoma

BACKGROUND

Making a preoperative pathologic diagnosis in patients with small lung nodules remains challenging. We have developed a new, noninvasive bronchoscopic microsampling probe to examine biochemical substances in epithelial lining fluid. We used this probe to measure tumor markers in fluid from tissues surrounding lung nodules less than 30 mm in diameter to test its adjunctive diagnostic utility in lung cancer.

METHODS

In 12 patients, epithelial lining fluid was collected in triplicate or duplicate from tissue within 2 cm of small peripheral lung nodules and from the contralateral lung. The diagnosis of adenocarcinoma was surgically confirmed in all patients. Fifteen patients without lung cancer served as controls. Concentrations of carcinoembryonic antigen, cytokeratin fragment 19, and sialyl SSEA-1 were measured in the fluid.

RESULTS

Carcinoembryonic antigen and cytokeratin fragment 19 concentrations were significantly higher in fluid near the nodules (median, 8.7 and 87.2 ng/mg, respectively) than on the contralateral sides (median, 1.5 and 3.7 ng/mg, respectively) or in fluid collected from the controls (median, 2.0 and 2.8 ng/mg, respectively).

CONCLUSIONS

Measurements of carcinoembryonic antigen and cytokeratin fragment 19 collected by our microsampling probe may be a useful diagnostic adjunct in patients with small peripheral lung nodules.

Peptide growth factors in tracheal aspirates of mechanically ventilated preterm neonates

Basic fibroblast growth factor (bFGF or FGF-2), vascular endothelial growth factor (VEGF), and endothelin-1 (ET-1) are peptide growth factors (PGF) mediating normal lung development, maturation, injury, and repair. These PGF may therefore be involved in the pathogenesis of bronchopulmonary dysplasia (BPD). We hypothesized that elevated levels of these PGF in tracheal aspirates would be associated with a) BPD and/or death; b) markers of cell injury and apoptosis; and c) chorioamnionitis, a risk factor for BPD. Tracheal aspirates collected in 29 preterm (<34 wk gestation, 500-2000 g birth weight), mechanically ventilated infants on d 1 of life were assayed for PGF and histone-associated DNA fragments by ELISA and for LDH by enzyme assay. Clinical and pathologic examination was performed for chorioamnionitis. BPD was defined as oxygen requirement/mechanical ventilation at 28 d postnatal age. The birth weight (mean +/- SE) was 1009 +/- 85 g and median gestational age was 26 wk (range, 22-33). Eighteen infants died or developed BPD. bFGF levels were elevated in infants who died or developed BPD [median (25%,75%) level of 36 (23, 44) pg/mL versus 14 (6, 30) in the survivors without BPD, p = 0.01]. bFGF levels correlated with apoptosis (r = 0.73, p < 0.001) and LDH levels (r = 0.59, p < 0.001). VEGF and ET-1 levels were not associated with apoptosis or with BPD/death. PGF levels were not associated with chorioamnionitis. We conclude that elevated bFGF levels in the preterm trachea correlate with BPD/death and markers of cell injury and apoptosis but not with chorioamnionitis. We speculate that bFGF may play a role in the development of BPD.

Hypothermia throughout intestinal ischaemia-reperfusion injury attenuates lung neutrophil infiltration

BACKGROUND/PURPOSE

Secondary organ damage to the lungs is an important consequence of intestinal ischaemia reperfusion (IIR) injury. Moderate hypothermia ameliorates gut necrosis and liver energy failure after IIR but potential beneficial effects on lung neutrophil infiltration after reperfusion of ischaemic bowel have not been investigated.

METHODS

Adult Sprague-Dawley rats underwent 60 minutes intestinal ischaemia followed by 120 minutes of reperfusion. The animals were maintained at either normothermia (36 degrees to 38 degrees C) or moderate hypothermia (30 degrees to 32 degrees C). Four groups were studied: (A) sham normothermia; (B) IIR normothermia; (C) sham hypothermia; and (D) IIR hypothermia. Lungs and terminal ileum were removed for measurement of myeloperoxidase activity (a marker of neutrophil infiltration). Results are expressed as milliunits per milligrams protein, mean +/- SEM, and one-way analysis of variance (ANOVA) with Tukey post-test was used for group comparisons.

RESULTS

Lungs: IIR at normothermia significantly increased lung neutrophil infiltration assessed by myeloperoxidase activity compared with sham-operated controls (normothermia sham 4.6 +/- 1.0, n = 8; normothermia IIR 37.7 +/- 13.8, n = 8; P =.011). Moderate hypothermia during IIR significantly attenuated lung neutrophil infiltration (7.2 +/- 2.1, n = 9) compared with normothermia IIR (P =.016) such that myeloperoxidase activity was similar to that found in sham normothermia (4.6 +/- 1.0, n = 8) and sham hypothermia (3.1 +/- 1.3, n = 8). Intestine: Gut myeloperoxidase activity was 0.9 +/- 0.5 in sham normothermia (n = 9) and 2.3 +/- 0.6 after normothermic IIR (n = 8). After IIR at hypothermia gut myeloperoxidase activity (0.5 +/- 0.2; n = 8) was significantly less than normothermic IIR (P =.035) and higher than sham hypothermia (0.2 +/- 0.1, n = 9; P =.01).

CONCLUSIONS

These results indicate that moderate hypothermia may prevent damage to another distant organ, ie the lungs, by preventing recruitment of neutrophils. This may be of benefit in decreasing distal organ damage in diseases in which intestinal ischaemia-reperfusion is implicated in the pathogenesis.