Leukotrienes in the sputum and urine of cystic fibrosis children

Role of Cystic Fibrosis Bronchial Epithelium in Neutrophil Chemotaxis

A hallmark of cystic fibrosis (CF) chronic respiratory disease is an extensive neutrophil infiltrate in the mucosa filling the bronchial lumen, starting early in life for CF infants. The genetic defect of the CF Transmembrane conductance Regulator (CFTR) ion channel promotes dehydration of the airway surface liquid, alters mucus properties, and decreases mucociliary clearance, favoring the onset of recurrent and, ultimately, chronic bacterial infection. Neutrophil infiltrates are unable to clear bacterial infection and, as an adverse effect, contribute to mucosal tissue damage by releasing proteases and reactive oxygen species. Moreover, the rapid cellular turnover of lumenal neutrophils releases nucleic acids that further alter the mucus viscosity. A prominent role in the recruitment of neutrophil in bronchial mucosa is played by CF bronchial epithelial cells carrying the defective CFTR protein and are exposed to whole bacteria and bacterial products, making pharmacological approaches to regulate the exaggerated neutrophil chemotaxis in CF a relevant therapeutic target. Here we revise: (a) the major receptors, kinases, and transcription factors leading to the expression, and release of neutrophil chemokines in bronchial epithelial cells; (b) the role of intracellular calcium homeostasis and, in particular, the calcium crosstalk between endoplasmic reticulum and mitochondria; (c) the epigenetic regulation of the key chemokines; (d) the role of mutant CFTR protein as a co-regulator of chemokines together with the host-pathogen interactions; and (e) different pharmacological strategies to regulate the expression of chemokines in CF bronchial epithelial cells through novel drug discovery and drug repurposing.

Comparative analyses of long non-coding RNA profiles in vivo in cystic fibrosis lung airway and parenchyma tissues

BACKGROUND

Recent advances in the functional analyses of endogenous non-coding RNA (ncRNA) molecules, including long non-coding RNAs (LncRNAs), have provided a new perspective on the crucial roles of RNA in gene regulation. Consequently, LncRNA deregulation is a key factor in various diseases, including pulmonary disorders like Cystic Fibrosis (CF). CF is the most common life limiting recessive disease in the U.S., and is due to mutations in the CFTR gene. CF mutations, of which the most common is F508del-CFTR, prevents correct folding, trafficking and function of the mutant CFTR protein and is further manifested by the hyper-expression of pro-inflammatory cytokines and chemokines into the airway lumen leading to bronchiectasis and culminating in lung destruction.

METHODS

Here we report a distinct LncRNA signature and corresponding mRNAs that distinguishes CF lung (airway and parenchyma) tissues from matched non-CF controls (n = 4 each group), generated by microarray specific for LncRNAs which includes corresponding mRNA expressions. In silico analyses of the cellular processes that are impacted by these LncRNAs was performed using Gene Ontology (GO). A selected subset of LncRNAs were validated by quantitative real-time PCR.

RESULTS

We have identified 636 LncRNAs differentially expressed in CF airway epithelium and 1974 in CF lung parenchyma compared to matched non-CF controls (fold change ≥2, p < 0.05), majority of which (> 50%) are intergenic. Interestingly, 15 of these differentially expressed LncRNAs and 9 coding mRNAs are common to airway and parenchyma tissues. GO analyses indicates that signaling pathways and cell membrane functions are significantly affected by the alteration in LncRNA expressions in CF lung tissues. Seven of the differentially expressed LncRNAs, exhibit similar expression trends in CFBE41o- compared to control cells.

CONCLUSION

Understanding the mechanisms by which these LncRNAs regulate CF disease phenotype will help develop novel therapeutic targets for CF and related pulmonary diseases, such as COPD and Asthma.

Abnormal unsaturated fatty acid metabolism in cystic fibrosis: biochemical mechanisms and clinical implications

Cystic fibrosis is an inherited multi-organ disorder caused by mutations in the CFTR gene. Patients with this disease exhibit characteristic abnormalities in the levels of unsaturated fatty acids in blood and tissue. Recent studies have uncovered an underlying biochemical mechanism for some of these changes, namely increased expression and activity of fatty acid desaturases. Among other effects, this drives metabolism of linoeate to arachidonate. Increased desaturase expression appears to be linked to cystic fibrosis mutations via stimulation of the AMP-activated protein kinase in the absence of functional CFTR protein. There is evidence that these abnormalities may contribute to disease pathophysiology by increasing production of eicosanoids, such as prostaglandins and leukotrienes, of which arachidonate is a key substrate. Understanding these underlying mechanisms provides key insights that could potentially impact the diagnosis, clinical monitoring, nutrition, and therapy of patients suffering from this deadly disease.

Quantitation of leukotriene B(4) in human sputum as a biomarker using UPLC-MS/MS

Leukotriene B4 (LTB4) is a potent mediator of inflammation and has been recognized as an important target for therapeutic intervention for treatment of diseases such as asthma. In the current work, a highly selective and sensitive UPLC-MS/MS assay was developed for quantitation of LTB4 in human sputum as a biomarker for LTB4 biosynthesis inhibition. A fit-for-purpose strategy for method development, assay qualification, and study support was adopted for this biomarker project. A surrogate matrix (protein buffer) was used for preparation of calibration samples and certain levels of quality control (QC) samples to avoid interference from endogenous analyte, while the low QC was prepared in authentic matrix, human sputum. The analytical methodology utilized a liquid-liquid extraction procedure in 96-well plate format. Chromatographic separation was achieved with a reversed-phase ultra high pressure liquid chromatography (UPLC) column using gradient elution, and the run time was 4.5min per sample. The lower limit of quantitation (LLOQ) was 0.2ng/mL, and the calibration curve range was 0.2-20ng/mL. Acceptable accuracy, precision, linearity, specificity, recovery, and matrix effect was obtained. Bench-top stability (6h), freeze-thaw stability (3 cycles at -20°C), and autosampler stability (97h at ambient temperature) all met acceptance criteria. Frozen long-term stability for 166 days at -20°C in sputum did not meet acceptance criteria by showing only ≥75% of nominal concentration and the information was taken into consideration for study support. Two important observations in the current work were: (1) LTB4 was unstable in sputum in the presence of liquification reagent dithiothreitol (DTT). Therefore, a non-DTT treatment method for sputum processing was developed and applied to the bioanalytical assay and clinical study support; and (2) chromatographic separation of LTB4 from its three non-enzymatically derived isomers, i.e. 6-trans-LTB4, 12-epi-LTB4, and 6-trans-12-epi-LTB4, was achieved. This assay was successfully applied to a Phase II clinical study for proof-of-concept of a LTA4 hydrolase inhibitor for treatment of asthma.

Metabolomic profiling of regulatory lipid mediators in sputum from adult cystic fibrosis patients

Retained respiratory tract (RT) secretions, infection, and exuberant inflammatory responses are core abnormalities in cystic fibrosis (CF) lung disease. Factors contributing to the destructive CF airway inflammatory processes remain incompletely characterized. The pro-oxidative inflammatory CF RT milieu is known to contain enzymatically and nonenzymatically produced regulatory lipid mediators, a panel of structurally defined oxidized metabolites of polyunsaturated fatty acids known to play a role in pathology related to inflammation. Using an extraction protocol that maximizes recoveries of sputum-spiked deuterated standards, coupled with an LC/MS/MS detection system, this study presents a metabolomic method to assess a broad spectrum of regulatory lipid mediators in freshly obtained sputum from CF patients. A broad range of both proinflammatory and anti-inflammatory lipid mediators was detected, including PGE2, PGD2, TXB2, LTB4, 6-trans-LTB4, 20-OH-LTB4, 20-COOH-LTB4, 20-HETE, 15-HETE, 11-HETE, 12-HETE, 8-HETE, 9-HETE, 5-HETE, EpETrEs, diols, resolvin E1, 15-deoxy-PGJ2, and LXA4. The vast majority of these oxylipins have not been reported previously in CF RT secretions. Whereas direct associations of individual proinflammatory lipid mediators with compromised lung function (FEV-1) were observed, the relationships were not robust. However, multiple statistical analyses revealed that the regulatory lipid mediators profile taken in aggregate proved to have a stronger association with lung function in relatively stable outpatient adult CF patients. Our data reveal a relative paucity of the anti-inflammatory lipid mediator lipoxin A4 in CF sputum. Patients displaying detectable levels of the anti-inflammatory lipid mediator resolvin E1 demonstrated a better lung function compared to those patients with undetectable levels. Our data suggest that comprehensive metabolomic profiling of regulatory lipid mediators in CF sputum should contribute to a better understanding of the molecular mechanisms underlying CF RT inflammatory pathobiology. Further studies are required to determine the extent to which nutritional or pharmacological interventions alter the regulatory lipid mediators profile of the CF RT and the impact of potential modulations of RT regulatory lipid mediators on the clinical progression of CF lung disease.

DHA and EPA reverse cystic fibrosis-related FA abnormalities by suppressing FA desaturase expression and activity

Patients and models of cystic fibrosis (CF) exhibit consistent abnormalities of polyunsaturated fatty acid composition, including decreased linoleate (LA) and docosahexaenoate (DHA) and variably increased arachidonate (AA), related in part to increased expression and activity of fatty acid desaturases. These abnormalities and the consequent CF-related pathologic manifestations can be reversed in CF mouse models by dietary supplementation with DHA. However, the mechanism is unknown. This study investigates this mechanism by measuring the effect of exogenous DHA and eicosapentaenoate (EPA) supplementation on fatty acid composition and metabolism, as well as on metabolic enzyme expression, in a cell culture model of CF. We found that both DHA and EPA suppress the expression and activity of Δ5- and Δ6-desaturases, leading to decreased flux through the n-3 and n-6 PUFA metabolic pathways and decreased production of AA. The findings also uncover other metabolic abnormalities, including increased fatty acid uptake and markedly increased retroconversion of DHA to EPA, in CF cells. These results indicate that the fatty acid abnormalities of CF are related to intrinsic alterations of PUFA metabolism and that they may be reversed by supplementation with DHA and EPA.

CYSTIC FIBROSIS SPUTUM STIMULATES CD18-INDEPENDENT NEUTROPHIL MIGRATION ACROSS ENDOTHELIAL CELLS

Excessive neutrophil recruitment to the lung underlies inflammatory-mediated lung damage in cystic fibrosis (CF). Neutrophils can migrate to the lung using either a CD18-dependent or CD18-independent mechanism. To determine if one of these migratory pathways is preferentially utilized by neutrophils migrating to the CF airways, this study examined the CD18 dependency of neutrophil transendothelial migration stimulated by the soluble fraction of CF sputum (SOL). Results demonstrate the preferential use of the CD18-independent migratory mechanism by both control and CF neutrophils and suggest that selective blocking of the CD18-independent migration pathway may offer a means of decreasing neutrophil influx to the CF airways.

Cysteinyl-leukotrienes and their receptors in asthma and other inflammatory diseases: critical update and emerging trends

Cysteinyl-leukotrienes (cysteinyl-LTs), that is, LTC4, LTD4, and LTE4, trigger contractile and inflammatory responses through the specific interaction with G protein-coupled receptors (GPCRs) belonging to the purine receptor cluster of the rhodopsin family, and identified as CysLT receptors (CysLTRs). Cysteinyl-LTs have a clear role in pathophysiological conditions such as asthma and allergic rhinitis (AR), and have been implicated in other inflammatory conditions including cardiovascular diseases, cancer, atopic dermatitis, and urticaria. Molecular cloning of human CysLT1R and CysLT2R subtypes has confirmed most of the previous pharmacological characterization and identified distinct expression patterns only partially overlapping. Interestingly, recent data provide evidence for the immunomodulation of CysLTR expression, the existence of additional receptor subtypes, and of an intracellular pool of CysLTRs that may have roles different from those of plasma membrane receptors. Furthermore, genetic variants have been identified for the CysLTRs that may interact to confer risk for atopy. Finally, a crosstalk between the cysteinyl-LT and the purine systems is being delineated. This review will summarize and attempt to integrate recent data derived from studies on the molecular pharmacology and pharmacogenetics of CysLTRs, and will consider the therapeutic opportunities arising from the new roles suggested for cysteinyl-LTs and their receptors.

Sputum biomarkers of inflammation in cystic fibrosis lung disease

Pulmonary biomarkers are being used more frequently to monitor disease activity and evaluate response to treatment in individuals with cystic fibrosis (CF). This article summarizes the current state of knowledge of biomarkers of inflammation relevant to CF lung disease, and the tools to measure inflammation, with specific emphasis on sputum. Sputum is a rich, noninvasive source of biomarkers of inflammation and infection. Sputum induction, through the inhalation of hypertonic saline, has expanded the possibilities for monitoring airway inflammation and infection, especially in individuals who do not routinely expectorate sputum. We critically examine the existing data supporting the validity of sputum biomarkers in CF, with an eye toward their application as surrogate endpoints or outcome measures in CF clinical trials. Further validation studies are needed regarding the variability of inflammatory biomarker measurements, and to evaluate how these biomarkers relate to disease severity, and to longitudinal changes in lung function and other clinical endpoints. We highlight the need to incorporate sputum collection, by induction if necessary, and measurement of sputum biomarkers into routine CF clinical care. In the future, pulmonary biomarkers will likely be useful in predicting disease progression, indicating the onset and resolution of a pulmonary exacerbation, and assessing response to current therapies or candidate therapeutics.

Inflammation and anti-inflammatory therapies for cystic fibrosis

Cystic fibrosis lung disease is characterized by a self-propagating cycle of obstruction, infection, and inflammation. The inflammatory response, which accounts for the majority of the morbidity and mortality of the disease, begins early in life, becomes persistent, and is excessive relative to the bacterial burden. Therapies aimed at decreasing the inflammatory response represent a relatively new strategy for treatment. This article reviews the current state of the art of anti-inflammatory therapy in cystic fibrosis and introduces clinical trials that are underway.

Peroxisome proliferator-activated receptor alpha (PPAR alpha) down-regulation in cystic fibrosis lymphocytes

Background

PPARs exhibit anti-inflammatory capacities and are potential modulators of the inflammatory response. We hypothesized that their expression and/or function may be altered in cystic fibrosis (CF), a disorder characterized by an excessive host inflammatory response.

Methods

PPARα, β and γ mRNA levels were measured in peripheral blood cells of CF patients and healthy subjects via RT-PCR. PPARα protein expression and subcellular localization was determined via western blot and immunofluorescence, respectively. The activity of PPARα was analyzed by gel shift assay.

Results

In lymphocytes, the expression of PPARα mRNA, but not of PPARβ, was reduced (-37%; p < 0.002) in CF patients compared with healthy persons and was therefore further analyzed. A similar reduction of PPARα was observed at protein level (-26%; p < 0.05). The transcription factor was mainly expressed in the cytosol of lymphocytes, with low expression in the nucleus. Moreover, DNA binding activity of the transcription factor was 36% less in lymphocytes of patients (p < 0.01). For PPARα and PPARβ mRNA expression in monocytes and neutrophils, no significant differences were observed between CF patients and healthy persons. In all cells, PPARγ mRNA levels were below the detection limit.

Conclusion

Lymphocytes are important regulators of the inflammatory response by releasing cytokines and antibodies. The diminished lymphocytic expression and activity of PPARα may therefore contribute to the inflammatory processes that are observed in CF.

Leukotriene receptor antagonists in children with cystic fibrosis lung disease : anti-inflammatory and clinical effects

Cystic fibrosis (CF) lung disease is characterized by chronic endobronchial infection resulting in progressive pulmonary destruction; this is a major cause of mortality and morbidity. Neutrophils are the primary effector cells responsible for the progressive deterioration of lung function. Peptido-leukotriene B4 antagonists, new anti-inflammatory agents that block the neutrophil-dominated inflammation, could have had the potential for long-term use. A trial on the pharmacokinetics of amelubant administered orally as a single dose of up to 75 mg in pediatric patients with CF and 300 mg in adults, and as a repeated dose of 75 mg and 150 mg, respectively, once daily for 15 days provided evidence that amelubant metabolism in adult and pediatric patients with CF is similar to that in healthy adults. In another study using the same dosage regimen, amelubant appeared to be safe and well tolerated. Safety measures included physical examination, vital signs, spirometry, oximetry, ECG, and clinical laboratory testing. However, a randomized, double-blind, placebo-controlled, multinational, phase II trial (Boehringer Ingelheim 543.45) was conducted to investigate the clinical efficacy of 24 weeks of treatment with amelubant in patients with CF with mild-to-moderate lung disease. Two doses of amelubant (75 and 150 mg) were tested in adult patients (> or = 18 years) and one dose of amelubant (75mg) was tested in pediatric (6-17 years) patients. The trial was terminated early due to a statistically significant increase in the risk of pulmonary-related, serious adverse events in adults receiving amelubant. Cysteinyl leukotrienes, eosinophilic inflammation, and viral infections also contribute to progressive pulmonary destruction in CF. Cysteinyl leukotrienes are potential targets for cysteinyl leukotriene receptor antagonist use. A study on the pharmacokinetics of montelukast in children with CF provided evidence that the dose of montelukast and the administration interval does not need to be modified if the goal is to mimic the serum concentrations used to treat asthma. In a randomized, double-blind, crossover, placebo-controlled study, 16 children with mild CF (median age 9.5 years; vital capacity [VC] >70%) were treated with montelukast (5 to < or =14 years; 5 mg; >14 years; 10 mg) or placebo as a once-daily tablet for 21 days. There was a significant (p < or = 0.02) reduction in serum eosinophil cationic protein levels and eosinophils (p < or = 0.027) with montelukast. However, neither lung function tests (VC, forced expiratory volume in 1 second [FEV1], maximum expiratory flow at 25% of forced VC), nor clinical symptom scores changed significantly. In another study, 26 patients aged 6-18 years with moderate CF (VC between 40% and 69% predicted) received montelukast or placebo for 8 weeks in a 20-week, randomized, double-blind, crossover, placebo-controlled trial. After treatment with montelukast there was a significant improvement in FEV1, peak expiratory flow, and forced expiratory flow between 25% and 75%, and a significant decrease in cough and wheezing scale scores (p < 0.001 for all). Montelukast treatment decreased serum and sputum levels of eosinophil cationic protein and interleukin-8 (IL-8), decreased sputum levels of myeloperoxidase, and increased serum and sputum levels of IL-10 (p < 0.001 for all) compared with placebo. To date, clinical experience and research data on the anti-inflammatory effects of leukotriene receptor antagonists in CF are limited. Multicenter trials with longer observation periods and greater patient numbers are needed to prove the hypothesis that leukotriene receptor antagonists have the potential to ameliorate CF lung disease with long term use.

Upregulation of COX-1 and COX-2 in nasal polyps in cystic fibrosis

BACKGROUND

Since abnormalities in prostanoid metabolism occur in the lower airway of patients with cystic fibrosis (CF), it is likely that they could also be detected in the nose.

METHODS

The degree of mRNA and protein expression of cyclo-oxygenase (COX) enzymes 1 (COX-1) and 2 (COX-2) was examined using quantitative reverse competitive polymerase chain reaction (RT-PCR) and Western blot analysis in the nasal polyps from 10 patients with CF, nasal polyps from 10 non-CF patients and 11 nasal mucosa specimens. The results are presented as 10(6) cDNA molecules/mug total RNA and the densitometric ratio between protein and beta-actin.

RESULTS

COX-1 mRNA levels were significantly higher in CF nasal polyps (median 2.34, 25-75th percentiles 1.6-3.2) than in the nasal mucosa (0.78, 0.11-1.21), while there was no difference with non-CF nasal polyps (1.11, 0.80-3.15). COX-1 protein levels were significantly higher in CF nasal polyps (3.63, 2.71-4.27) than in nasal mucosa (1.55, 0.66-2.33) and non-CF nasal polyps (2.19, 1.72-3.68). COX-2 mRNA was significantly higher in CF nasal polyps (3.34, 2.42-7.05) than in nasal mucosa (1.69, 0.19-3.50). No differences were found in COX-2 mRNA expression between CF and non-CF polyps (1.38, 0.12-6.07). COX-2 protein levels were also significantly higher in CF nasal polyps (0.23, 0.04-0.34) than in non-CF nasal polyps (0.011, 0.009-0.016) or nasal mucosa (0.014, 0.014-0.016).

CONCLUSIONS

Upregulation in the expression of COX-1 and COX-2 could explain the high production of prostanoids reported in CF. These findings raise questions regarding the potential use of selective or non-selective COX-2 non-steroidal anti-inflammatory treatment in CF.

Effects of montelukast treatment on clinical and inflammatory variables in patients with cystic fibrosis

BACKGROUND

In cystic fibrosis (CF), the inflammatory process contributes to progressive lung tissue damage. Cysteinyl leukotrienes have been found in the sputum of patients with CF at high concentrations sufficient to cause potent biological effects.

OBJECTIVE

To evaluate the effect of anti-inflammatory treatment with montelukast sodium in patients with CF.

METHODS

Twenty-six patients aged 6 to 18 years were recruited to this 20-week, randomized, double-blind, placebo-controlled, crossover trial. Patients received montelukast or placebo for 8 weeks in addition to their regular CF treatment. Before and after treatment, findings from spirometry, whole-body plethysmography, and the clinical wheezing and cough scales were evaluated. At the same time, serum and sputum samples were obtained for the measurement of eosinophil cationic protein, interleukin 10 (IL-10), IL-8, and myeloperoxidase levels.

RESULTS

Twenty-three patients completed the study. Compared with placebo use, montelukast treatment significantly improved forced expiratory volume in I second, peak expiratory flow, and forced expiratory flow between 25% and 75% and significantly decreased cough and wheezing scale scores (P < .001 for all). There were no significant changes in vital capacity, thoracic gas volume, airway resistance, and residual volume after treatment. Compared with placebo use, montelukast treatment decreased serum and sputum levels of eosinophil cationic protein and IL-8, decreased sputum levels of myeloperoxidase, and increased serum and sputum levels of IL-10 (P < .001 for all).

CONCLUSIONS

Montelukast may have measurable anti-inflammatory properties in patients with CF.

Is there a case for n-3 fatty acid supplementation in cystic fibrosis?

PURPOSE OF REVIEW

This review evaluates our current knowledge on the association of fatty acid abnormalities in cystic fibrosis with the disease process, and makes a case for a well-designed clinical trial to evaluate the clinical efficacy of long chain n-3 fatty acids.

RECENT FINDINGS

It has long been known that cystic fibrosis patients exhibit fatty acid abnormalities, but these have not been well investigated in tissues affected by the disease. Recent studies have demonstrated that such tissues do indeed show abnormalities in the proportions of linoleic, arachidonic and docosahexaenoic acids, and have demonstrated alterations in fatty acid and phospholipid metabolism in cystic fibrosis. Work in other areas has identified novel anti-inflammatory actions of long chain n-3 fatty acids that might be relevant to cystic fibrosis. A recent systematic review of fish oil supplementation in cystic fibrosis did not allow firm conclusions to be drawn, but suggested that there may be some benefits.

SUMMARY

The restoration of abnormal fatty acid profiles may be beneficial in cystic fibrosis, but this approach has not been evaluated in studies with a suitable design to permit firm conclusions to be drawn. There is a need for a long-term randomized controlled study to evaluate the therapeutic benefit of fish oil supplementation in cystic fibrosis.

A pilot study of zafirlukast as an anti-inflammatory agent in the treatment of adults with cystic fibrosis

BACKGROUND

Persistent endobronchial inflammation is in part responsible for the attrition of lung function seen in cystic fibrosis. Leukotrienes act as pro-inflammatory mediators. The aim of this study was to assess the efficacy of the leukotriene receptor antagonist zafirlukast as a potential anti-inflammatory agent in the treatment of adult patients with cystic fibrosis.

METHODS

Clinically stable patients were enrolled in the study if they had no history or clinical evidence of asthma, bronchial hyper-reactivity, or aspergillosis. They were randomised to receive zafirlukast 20 mg twice daily with all routine treatment for four months or routine treatment alone in an open cross-over design. Primary endpoints were changes in respiratory function tests and a modified NIH clinical score.

RESULTS

Thirty patients were enrolled and 25 completed. There was a significant improvement in the modified NIH clinical score but no significant increase in respiratory function with zafirlukast.

CONCLUSIONS

Patients receiving a leukotriene receptor antagonist in addition to routine treatments showed significant improvement in a clinical score which is a composite of clinical wellbeing, chest radiograph appearance, and physical examination. Respiratory function showed a non-significant trend towards improvement with treatment. Zafirlukast may benefit patients with CF. An adequately powered study is justified on the basis of these results.

LTB4 is present in exudative pleural effusions and contributes actively to neutrophil recruitment in the inflamed pleural space

The pleural space is a virtual compartment between the lung and chest wall that becomes filled with fluid and inflammatory cells during a variety of respiratory diseases. Here, we study the potential role of the eicosanoid metabolite leukotriene B4 (LTB4) in disparate diseases leading to acute (pneumonia) or chronic (tuberculosis, cancer) inflammation of the pleural space. LTB4 concentrations were significantly higher in pleural fluid due to pneumonia, tuberculosis and cancer with respect to congestive heart failure and correlated with neutrophil elastase, which is used as an indication of state of activation of neutrophils in the pleural space. Moreover, pleural LTB4 was biologically active, as an anti-LTB4 antibody partially neutralized the chemotactic activity of parapneumonic, tuberculous and cancer effusions. Macrophages, neutrophils, lymphocytes, mesothelial cells and cancer cells all expressed mRNA for 5-lipoxygenase, the enzyme that initiates leukotriene synthesis leading to the production of LTB4, in exudative pleural effusions. Upon stimulation in transudative pleural effusions, pleural macrophages produced, in a time-dependent fashion, a significantly higher concentration of LTB4 than mesothelial cells. These studies demonstrate that different cell types are capable of producing LTB4 in the inflamed pleural space and that this mediator may play a crucial role in the recruitment of neutrophils into the pleural space.

Ion trap liquid chromatography/tandem mass spectrometry analysis of leukotriene B4 in exhaled breath condensate

The objective of this study is the measurement of leukotriene B7 (LTB4), a potent inflammatory mediator, in exhaled breath condensate by using liquid chromatography/mass spectrometry (LC/MS and LC/MS/MS). Condensation of exhaled breath is a non-invasive method to collect airway secretions. Deuterated (d4)-LTB4 was used as internal standard. The MS and MS/MS behavior of LTB4 and LTB4-d4 was studied by electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in both positive and negative ion polarity mode. Preliminary results show that monitoring negative ions in ESI mode has the best sensitivity for both LTB4 and LTB4-d4. Therefore, negative ESI was chosen, and the [M-H]- ions at m/z 335 and 339 were selected for quantification. The lower limit of quantification for LTB4, expressed as the lowest point of the calibration curve, was 100 pg/mL. Using this technique, we measured LTB4 in exhaled breath condensate in two healthy subjects, four asthmatic patients on anti-inflammatory treatment, and four asthmatic patients who were not on anti-inflammatory drugs. Exhaled LTB4 concentrations were detected only in asthmatic patients who were not on anti-inflammatory therapy. This method is potentially useful for non-invasive assessment of airway inflammation, but the sensitivity of the technique needs to be improved.

Pharmacological approaches for the discovery and development of new anti-inflammatory agents for the treatment of cystic fibrosis

Some of the most important pathobiology in cystic fibrosis occurs not as a direct result of impaired chloride transport, but the downstream consequences of defective CFTR function, particularly the lung infection and inflammation that ultimately takes the lives of most patients. Interrupting the vicious cycle of infection and inflammation is effective in slowing the course of the disease, and antibiotics have long been the staple of pulmonary therapy. However, limiting the inflammatory response in the CF lung is also effective. High dose ibuprofen clearly retards progression of lung disease, but also entrains adverse events that mar its therapeutic utility, so alternative anti-inflammatory agents are necessary. Because of the remarkable therapeutic success of ibuprofen, consideration should be given to finding less toxic alternatives. However, it is also appropriate to consider the mechanisms by which the inflammatory response occurs in the CF lung, and identify sites to interrupt it. Sites at which therapeutic intervention is possible are the neutralization of cytokines such as tumor necrosis factor-alpha, interleukin (IL)-1beta, or IL-8 with specific antibodies or receptor antagonists, inhibition of the intracellular signaling cascades that result in cytokine production (for example, at the level of p38 MAP kinase), application of cytokines such as Il-10 that are themselves anti-inflammatory, or modulating the arachidonic acid cascade with inhibitors directed at leukotriene B(4). In addition, interventions designed to limit the consequences of the inflammatory response, such as protease inhibitors and reagents to limit the ill effects of DNA accumulation in airways, are in use. To limit adverse effect and concentrate the therapeutic effect, there may be value in targeting delivery of the therapeutic reagents to the inflamed site, either by specifically directing systemic delivery or by exploitation of the aerosol route. Treating the inflammatory response is important, for the data from the ibuprofen study show that the effects of anti-inflammatory therapy are additive or even synergistic with intensive conventional therapy and alter the rate of decline of pulmonary function, and therefore benefits for survival of patients with CF are to be expected.

Anti-inflammatory effects of montelukast in mild cystic fibrosis

BACKGROUND

Immune-mediated inflammation contributes to progressive pulmonary damage in cystic fibrosis (CF). Sputum cysteinyl leukotriene levels, eosinophil cationic protein (ECP), and interleukin-8 (IL-8) are significantly related to disease severity.

OBJECTIVE

The aim of this study was to evaluate the anti-inflammatory and clinical effects of the cysteinyl leukotriene receptor antagonist montelukast in children with CF.

METHODS

A double-blind, randomized, crossover design was used. Patients received montelukast (6 to < or = 14 years, 5 mg; > 14 years, 10 mg) or placebo as a once-daily tablet for 21 days and then, after a washout period of at least 4 weeks, crossed over to receive the alternative treatment. Blood and native nasal fluid were taken on days 1 and 21 of each treatment block, and WBC count, ECP, and IL-8 were analyzed using a chemiluminescent immunometric assay.

RESULTS

Sixteen CF patients (10 boys, 6 girls; age, 5 to 18 years, median 9.5 years) completed the trial. There was a significant (P < or = 0.02) reduction of serum ECP (median reduction: montelukast 7.7 microg/L vs placebo 0.15 microg/L) and eosinophils (P < or = 0.027; median reduction: montelukast 85/microL vs placebo 0/microL). There was no significant change in nasal ECP, IL-8, or serum IL-8 after a 21-day course of montelukast. Clinical symptom scores did not change significantly.

CONCLUSIONS

Montelukast reduces eosinophilic inflammation in CF patients. Multicenter trials providing more patients to create more data to prove the hypothesis that montelukast is an effective tool to cut down disease severity in CF patients are needed.

Urinary leukotriene E(4) excretion during the first month of life and subsequent bronchopulmonary dysplasia in premature infants

BACKGROUND

Inflammation plays an important role in the pathogenesis of bronchopulmonary dysplasia (BPD), but the exact nature of this inflammatory process is incompletely understood. Older infants with established BPD have higher levels of urinary leukotriene E(4) (LTE(4)) compared to healthy infants of the same age. This suggests that cysteinyl leukotrienes may play a role in the abnormalities seen in BPD.

OBJECTIVES

To measure urinary LTE(4) levels during the first month of life in premature infants, and to determine whether there are significant differences in premature infants who develop BPD, as compared to those who do not develop BPD.

DESIGN

Prospective, blinded, controlled study.

SETTING

Neonatal ICUs of a tertiary-care university hospital.

METHODS

Thirty-seven premature infants (< 33 weeks of gestational age) were enrolled prospectively at birth. Urinary LTE(4) levels were measured blinded, using a standard radioimmunoassay technique at 2 days, 7 days, and 28 days of life. At 1 month of age, infants were classified as with or without BPD, based on need for supplemental oxygen, and characteristic chest radiographs. Clinical features and urinary LTE(4) were compared between the two groups.

RESULTS

Mean +/- SD gestational age was 29 +/- 2.6 weeks. None of the infants had a family history of asthma. Thirteen of 37 infants were classified as having BPD at 28 days after birth. Mean gestational age in infants who developed BPD was 27 +/- 2.4 weeks, compared to 30 +/- 2 weeks in infants who did not develop BPD (p < 0.05). In infants with BPD, mean urinary LTE(4) levels of urinary creatinine were 1,762 +/- 2,003 pg/mg, 1,236 +/- 992 pg/mg, and 5,541 +/- 5,146 pg/mg at days 2, 7, and 28, respectively, compared to 1,304 +/- 1,195 pg/mg, 1,158 +/- 1,133 pg/mg, and 2,800 +/- 2,080 pg/mg in infants without BPD. LTE(4) levels at 2 days, 7 days, and 28 days did not correlate with the subsequent development of BPD. LTE(4) levels at day 28 were significantly higher than LTE(4) levels at day 2 and day 7 in both groups, even after correcting for gestational age or birth weight (p < 0.05). There was significant inverse correlation between LTE(4) levels at day 2 with gestational age and birth weight (p < 0.05). All 13 infants with BPD received steroid pulses, compared to 3 of 26 infants without BPD. Gestational age and use of postnatal steroid pulses, diuretics, and theophylline (for apnea of prematurity) were significantly associated with each other and with the subsequent development of BPD.

CONCLUSION

Urinary LTE(4) levels measured on the second day of life in very-low-birth-weight infants inversely correlate with gestational age and birth weight. Urinary LTE(4) levels may reflect lung injury and/or inflammation in premature infants, not necessarily related to BPD as it is presently defined.

Production of the potent neutrophil chemokine, growth-related protein alpha (GROalpha), is not elevated in cystic fibrosis children

Progressive neutrophil-mediated lung damage causes much of the morbidity and mortality in cystic fibrosis (CF). Neutrophil chemoattractants implicated in CF include interleukin (IL-)8, tumour necrosis factor (TNFalpha) and leukotriene (LT)B4, but growth-related protein alpha (GROalpha), a highly potent neutrophil chemokine, has not been investigated. Atopic status has been considered to contribute to the marked heterogeneity of pulmonary disease in CF. We hypothesized that GROalpha may be produced in biologically-significant amounts in the CF lung, and that enhanced production of GROalpha, IL-8 or LTB4 may contribute to the poorer lung function seen in atopic CF patients compared to non-atopic CF patients. GROalpha, IL-8 and LTB4 levels in the sputum of atopic and non-atopic CF patients were assessed by immunoassays, and GROalpha and IL-8 levels were also assessed in the plasma of CF patients and normal controls. As expected, there were high levels of IL-8 and LTB4 in most CF sputum samples, and IL-8 levels were higher in CF plasma than in control plasma (P=0.02). In contrast, GROalpha was undetectable (< 5 pg ml(-1)) in the sputum of 21 out of 25 CF patients, with low levels (range 144-825 pg ml(-1)) in the remainder, and median levels of GROalpha in CF plasma (33 pg ml(-1), n=24) were not significantly different from controls (34 pg ml(-1), n=25). Lung function [forced expiratory volume in 1 sec (FEV1) and forced vital capacity (FVC)] was significantly poorer in atopic CF compared to non-atopic CF patients (P<0.02), but sputum levels of GROalpha, IL-8 and LTB4 were not different between the subgroups. Our results suggest that unlike LTB4 and IL-8, GROalpha does not contribute to neutrophilic inflammation in the CF lung, and other factors must determine the impaired lung function observed in atopic CF patients. These results may have important implications in the development of chemokine receptor antagonists as novel anti-inflammatory agents in CF.

Application of gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry to assess in vivo synthesis of prostaglandins, thromboxane, leukotrienes, isoprostanes and related compounds in humans

Prostaglandins, thromboxane, leukotrienes, isoprostanes and other arachidonic acid metabolites are structurally closely related, potent, biologically active compounds. One of the most challenging tasks in eicosanoids research has been to define the role of the various eicosanoids in human health and disease, and to monitor the effects of drugs on the in vivo synthesis of these lipid mediators in man. Great advances in instrumentation and ionization techniques, in particular the development of tandem mass spectrometry and negative-ion chemical ionization (NICI), in gas chromatography and also advances in methodologies for solid-phase extraction and sample purification by thin-layer chromatography and high-performance liquid chromatography have been made. Now gas chromatography-mass spectrometry (GC-MS) and GC-tandem MS in the NICI mode are currently indispensable analytical tools for reliable routine quantitation of eicosanoid formation in vivo in humans. In this article analytical methods for eicosanoids based on GC-MS and GC-tandem MS are reviewed emphasizing the quantitative measurement of specific index metabolites in human urine and its importance in clinical studies in man. Aspects of method validation and quality control are also discussed.

The chemotactic activity of sputum from patients with bronchiectasis

Persistent polymorphonuclear neutrophil (PMN) recruitment to airway is thought to be an important component of continuing inflammation and progression of chronic destructive lung diseases. Although chemoattractants are required for the PMN to migrate, the nature of the chemoattractants in the airways has not yet been clarified. We therefore investigated the contribution of interleukin-8 (IL-8) and leukotriene-B4 (LTB4) to the chemotactic activity of lung secretions by inhibiting their activity using a monoclonal antibody to IL-8 and an LTB4 receptor antagonist (LY293111 sodium). Fifty-nine sputum samples obtained from 19 patients with bronchiectasis were studied. In preliminary studies the chemotactic responses to IL-8 and LTB4 were found to be additive, and we were able to remove their contribution independently with the appropriate antibody and antagonist. The chemotactic activity of the secretions was related to the macroscopic appearance (mucoid, mucopurulent, and purulent), and this appeared to be related to an increase in IL-8 contribution. Chemotactic activity was reduced by antibiotic therapy and again that seemed to relate to a reduction in the IL-8 contribution. The contributions of LTB4 were similar among the three types of sputum in varying clinical states. These data suggest that LTB4 and IL-8 are important chemotactic factors in lung secretions from such patients, although IL-8 appears to play a more important role during acute exacerbations. These results may be useful in determining therapeutic strategies for chronic destructive lung diseases in the future.

[Potential importance of antileukotrienes in the treatment of asthma and other inflammatory diseases: apropos of a new pharmacological class]

OBJECTIVES

Among the mediators involved in the asthma bronchoconstriction and inflammation mechanisms, there is now substantial evidence that the sulfidopeptide leukotrienes (LTs) are important. Antagonists of their receptors and inhibitors of their synthesis have been developed.

IMPORTANT POINTS

Antagonists of LTs, as well as inhibitors of their synthesis, reduce the LTs actions: bronchoconstriction, bronchial hyperresponsiveness, hypersecretion and inflammation. They produce an acute bronchodilating effect in mild asthma, reduce the hyperresponsiveness responses due to allergens, aspirin and cold and dry air, and also cutaneous and gastrointestinal reactions. Oral administrations tested during 4 or 6 weeks diminish the use of the beta-agonists, decrease the asthma symptom scores and other inflammatory signs.

PERSPECTIVES AND PROJECTS

More studies for longer periods, double blind trials and comparisons with classical treatments will be necessary to define the real place of LTs antagonists in the treatment of asthma. So their efficacy has to be confirmed as well as their good tolerance profile (particularly for hepatic functions).

CONCLUSION

Antagonists of receptors and synthesis inhibitors of LTs have known a recent and important development. They constitute a new therapeutic class: further studies are needed to better define the place of these new drugs in the treatment of asthma and other inflammatory diseases.

Eicosanoid mediator expression in mononuclear and polymorphonuclear cells in normal subjects and patients with atopic asthma and cystic fibrosis

BACKGROUND

Eicosanoids such as leukotrienes, prostaglandins, lipoxins, and 15-hydroperoxyeicosatetraenoic acid (15-HETE) cause bronchoconstriction, increased microvascular permeability, mucus secretion, and polymorph chemotaxis. These pro-inflammatory effects are important in diseases such as asthma and cystic fibrosis where the levels of mediators are increased both in the stable and acute state. A study was conducted to examine the expression of the mRNA for the enzymes of the eicosanoid pathways (5-lipoxygenase (5-LO), 5-lipoxygenase activating protein (FLAP), cyclo-oxygenases 1 and 2 (COX-1, COX-2), and 15-lipoxygenase (15-LO)) in normal subjects and in patients with stable atopic asthma and stable cystic fibrosis.

METHODS

Reverse transcription polymerase chain reaction (RT-PCR) was used to examine the expression of total RNA for 5-LO, FLAP, COX-1, COX-2, and 15-LO in peripheral blood polymorphonuclear cells and mononuclear cells from the three subjects groups.

RESULTS

The expression of mRNA for 5-LO and FLAP was similar in normal subjects and in patients with asthma and cystic fibrosis. COX-1 was increased in both cell types in asthmatic patients. COX-2 and 15-LO were increased in polymorphs of patients with atopic asthma but not in mononuclear cells. COX-2 and 15-LO were undetectable in either cell type in patients with cystic fibrosis whereas COX-1 levels in polymorphs were similar to those in patients with asthma.

CONCLUSIONS

The increased leukotriene production in asthma and cystic fibrosis is not explained by an increase in transcription of 5-LO and FLAP. Transcription of 15-LO and COX-2 is increased in atopic asthma. Transcription of COX-1 is increased in both atopic asthma and cystic fibrosis.

Analytical methods for the measurement of leukotrienes and other eicosanoids in biological samples from asthmatic subjects

This paper summarizes methodological aspects of measurements of eicosanoids in biological samples and describes some applications of such methods in studies on leukotriene formation in the human airways and the effects of drugs interfering with these compounds in asthmatic subjects. For estimations of in vivo production of eicosanoids, major, stable metabolites were selected for analysis in biological fluids. An enzyme immunoassay for LTE4 was validated for use in unextracted urine samples. To monitor thromboxane production, a radioimmunoassay for 11-dehydro-TXB2 was developed and used for measurements in samples of human plasma and urine. In vitro production of leukotrienes in chopped human lung was measured by UV-spectroscopy after extraction and separation on RP-HPLC. Corrections for losses during purification were performed with individually selected internal standards.

Persistent increase in plasma and urinary leukotrienes after acute asthma

Leukotrienes may mediate bronchoconstriction in asthma. Cysteinyl leukotriene production rises in vivo after allergen challenge, but few reports describe leukotriene concentrations in clinical asthma or in children. Using high performance liquid chromatography/radioimmunoassay, plasma and urinary leukotrienes in asthmatic children (aged 5-10 years) were measured during an acute exacerbation (peak expiratory flow (PEF) < 65%, n = 10) and one month later (PEF 74-169%, n = 9), and in non-atopic normal children (aged 1.3-13.2 years). In the asthmatics, geometric mean (95% confidence interval) plasma leukotriene B4 (LTB4) was 746 pg/ml (398 to 1403) acutely and 1026 pg/ml (662 to 1593) in remission, compared with 369 pg/ml (167 to 728) in the normal children (n = 14). Plasma cysteinyl leukotrienes were low or undetectable, but urinary leukotriene E4 (LTE4) was higher in the asthmatics during an acute episode (210 pmol/mmol creatinine, 101 to 454) and at follow up (179 pmol/mmol, 110 to 293), compared with the normal children (98 pmol/mmol, 81 to 118, n = 41). This persistent increase in plasma LTB4 and urinary LTE4 concentrations one month after a severe asthmatic episode suggests leukotriene production is related to chronic inflammation rather than to acute bronchoconstriction.

Chemical synthesis of dioxygen-18 labelled omega-/beta-oxidized cysteinyl leukotrienes: analysis by gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry

Cysteinyl leukotrienes (LT) C4, LTD4 and LTE4 are potent mediators of anaphylaxis and inflammation. LTE4 is extensively metabolized in man mainly by omega-oxidation followed by subsequent beta-oxidation to more polar and biologically inactive metabolites. This paper describes a method for the synthesis of [1,20-18O2]-carboxy-LTE4, [1,18-18O2]-carboxy-dinor-LTE4, and [1,16-18O2]-carboxy-14,15-dihydro-tetranor-LTE4 starting from the unlabelled dimethyl esters of 20-carboxy-LTA4, 18-carboxy-dinor-LTA4 and 16-carboxy-14,15-dihydro-tetranor-LTA4, respectively, by separate chemical conjugation with cysteine hydrochloride in H2-18O-methanol followed by alkaline hydrolysis with Li18OH. The isotopic purity of the isolated reaction products was 94% at 18O for all three preparations while only 0.3% remained unlabelled as confirmed by negative-ion chemical-ionization gas chromatography-mass spectrometry (GC-NICI-MS) after their catalytical reduction/desulphurization and derivatization. The 18O2-labelled compounds are demonstrated to be suitable internal standards for quantification by GC-NICI-MS and GC-NICI-tandem MS. We found by GC-NICI-tandem MS that the excretion rate of 20-carboxy-LTE4 is comparable to that of LTE4 (both in nmol/mol creatinine, mean +/- S.E.) in healthy children (26.7 +/- 4.7 vs. 32.0 +/- 6.0, n = 9) and adults (13.9 +/- 1.1 vs. 27.2 +/- 5.4, n = 3).

Validation and application of a new simple strategy for measurements of urinary leukotriene E4 in humans

To monitor endogenous production of cysteinyl-containing leukotrienes, the end-metabolite leukotriene E4 (LTE4) was analysed in urine. Results obtained with a sensitive enzyme immunoassay (EIA), performed on crude urine samples correlated well with data obtained from a previously reported radioimmunoassay. Enzyme immunoassay analysis of unextracted urine was justified by an excellent agreement between analyses in crude samples and measurements achieved after purification on solid phase extraction followed by separation on reversed-phase high performance liquid chromatography. Moreover, LTE4 was stable in urine samples stored at -20 degrees C, for months without the addition of preservatives. The stability of LTE4 in urine was not improved by addition of the antioxidant 4-hydroxy-TEMPO and pH adjustment to 9. As assessed by EIA analysis in crude urine samples, baseline values for urinary leukotriene E4 were not significantly different between atopic asthmatic subjects and non-asthmatic individuals, and there was no diurnal variation in urinary excretion of LTE4 in healthy subjects. However, we confirmed earlier data on significantly higher basal levels of urinary LTE4 in aspirin-intolerant asthmatics. In addition, a post-challenge increase in urinary LTE4 levels was detected in association with allergen-induced airway obstruction in atopic asthmatics. The per cent increase in urinary LTE4 was similar, irrespective of whether the samples were purified or not prior to EIA. Thus, combined with random validation by high performance liquid chromatography, the strategy of direct EIA of serially diluted urine samples was found to be a good index of in vivo production of leukotrienes. This was further reinforced by the demonstration that pretreatment with the leukotriene biosynthesis inhibitor Bay x 1005 inhibited the post allergen-challenge increase in urinary LTE4, as shown both with unpurified and purified samples.

Defective inhibition by dexamethasone of leukotriene B4 and C4 production by leukocytes in patients with cystic fibrosis

To investigate the effects of glucocorticoids on leukotriene (LT) generation in patients with cystic fibrosis (CF), we evaluated calcium ionophore A23187-induced LTB4 and LTC4 production by leukocytes with and without pretreatment with dexamethasone. The CF patients were in good condition and did not have acute infection. There were no significant differences in LTB4 and LTC4 production without dexamethasone pretreatment between the CF patients and controls. However, the ratios of LTB4 and LTC4 production by leukocytes preincubated with dexamethasone to those of leukocytes without dexamethasone pretreatment were significantly higher in the CF patients than in the controls (both p < 0.05). Our data suggest that the response of LTB4 and LTC4 production to dexamethasone is disturbed in patients with CF. The generation of LTs may be enhanced due to a disturbance in glucocorticoid suppression.

Eicosapentaenoic acid modulates neutrophil leukotriene B4 receptor expression in cystic fibrosis

In patients with cystic fibrosis (CF), high intrapulmonary concentrations of the neutrophil chemotaxin leukotriene B4 (LTB4) are associated with specific reduction of LTB4-induced chemotaxis of circulating neutrophils. The chemotactic abnormality is partially corrected by dietary supplementation with eicosapentaenoic acid (EPA). LTB4-induced neutrophil chemotaxis is mediated by specific, high-affinity, cell surface LTB4 receptors. The hypotheses that neutrophil LTB4 receptors are down-regulated in CF, and that EPA normalizes receptor expression, were tested by measuring the number (Rmax) and affinity (Kd) of LTB4 receptors on neutrophils from eight CF patients before and after EPA (6 weeks of 2.7 g/day), and from nine normal individuals. High-affinity receptor Rmax was depressed in CF patients (0.6 +/- 0.2 x 10(4)/cell (mean +/- s.d.) versus 1.8 +/- 0.7 x 10(4)/cell in normals), but corrected to normal (2.0 +/- 1.9 x 10(4)/cell) after EPA. High-affinity receptor Kd was depressed in CF patients (0.4 +/- 0.3 nM versus 1.4 +/- 0.5 nM in normals), and also corrected to normal with EPA (1.4 +/- 1.2 nM). Low-affinity receptors were depressed, but did not change significantly with EPA. These results indicate that neutrophil responses in chronic inflammatory lung disease can be influenced directly by LTB4 receptor modulation, and that this effect of EPA predominates over alterations in neutrophil signal transduction in situations of chronic exposure to LTB4.

Oral absorption of omega-3 fatty acids in patients with cystic fibrosis who have pancreatic insufficiency and in healthy control subjects

Dietary supplementation with fish oils high in the omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, may have an antiinflammatory effect. We determined whether patients with cystic fibrosis (CF) could incorporate omega-3 fatty acids into their plasma and cell membrane phospholipids without adverse effects. In this double-blind study, 12 patients with pancreatic insufficiency who have CF (mean age, 12.2 +/- 5.4 (SD) years) and 13 subjects without CF (mean age, 13.4 +/- 6.3 (SD) years) were randomly assigned to ingest 8 gm daily of either encapsulated fish oil (3.2 gm of eicosapentaenoic acid and 2.2 gm of docosahexaenoic acid daily) or olive oil ethyl esters for 6 weeks. Two of seven and two of five patients with CF who received fish and olive oils, respectively, and one of eight and none of five subjects without CF discontinued taking the capsules before 6 weeks because of eructation or diarrhea. Significant incorporation of omega-3 fatty acids into plasma and erythrocyte membrane phospholipids was observed in subjects with and those without CF randomly assigned to the fish oil treatment. For example, in subjects randomly assigned to receive fish oil, the eicosapentaenoic acid/arachidonic acid ratio in plasma increased 9.8-fold, from 0.04 +/- 0.02 (mean +/- SEM) to 0.39 +/- 0.11 (p = 0.02), in the patients with CF (n = 7) and 23.0-fold, from 0.04 +/- 0.01 to 0.92 +/- 0.17 (p = 0.001), in the subjects without CF (n = 8) who received fish oil (p = 0.02, patients with CF vs subjects without CF at 6 weeks). No clinically or statistically significant changes from baseline were observed in platelet aggregation or levels of vitamin E or A in subjects who received fish oil. Future studies are indicated to determine whether omega-3 fatty acid enrichment provides a clinically beneficial antiinflammatory effect in patients with CF.

Outcome measures for clinical trials in cystic fibrosis. Summary of a Cystic Fibrosis Foundation consensus conference

The CFF Consensus Conference concluded with a summary of those outcome measures that would be most useful in studies of patients 6 years of age and older and those measures that would be most useful in studies of the younger population (< 6 years of age) (Table). These measures were further divided into biologic markers most appropriate for initial (phase I and phase II) clinical trials and those especially useful in large, multicenter (phase III) pivotal trials. There is an ongoing need to improve the accuracy and validity of currently available measures of biologic activity and clinical efficacy in CF, especially in the younger population. The conference participants recommended that the following eight issues be addressed as soon as possible: (1) definition of pulmonary exacerbation, (2) broadly applicable methods of testing pulmonary function in small children (ideally a single test for all ages), (3) a comprehensive severity-of-disease score for young children, (4) reliable methods of quantifying chest x-ray and CT scan changes in young patients, (5) simple, inexpensive measures of lung inflammation, (6) a centralized, uniform approach to the establishment of data monitoring committees, (7) a quality of well-being scale for small children, and (8) reliable, reproducible aerosol delivery systems with defined characteristics. In addition, participants recommended that better methods be developed for assessing patients' adherence to research protocols.

Leukotriene B4 markedly elevated in the epithelial lining fluid of patients with cystic fibrosis

Persistent neutrophil infiltration into the airways of patients with cystic fibrosis (CF) results in lung destruction. Eicosanoid lipid mediators, particularly leukotriene B4 (LTB4), may play a role in neutrophil influx and activation. We compared the eicosanoid content of epithelial lining fluid (ELF) obtained by bronchoalveolar lavage (BAL) from 17 patients with CF and 10 healthy subjects. LTB4 was the predominant eicosanoid in the CF airway (16.7 +/- 9.1 ng/ml ELF in CF versus 0.5 +/- 0.1 ng/ml ELF in healthy subjects). Prostaglandins (PG) and thromboxane (TX) were also elevated in CF (PGE2, 8.5 +/- 2.2; PGF2 alpha, 6.0 +/- 2.0; and TXB2, 14.0 +/- 3.0 ng/ml ELF) compared with healthy subjects (PGE2, 0.4 +/- 0.2; PGF2 alpha, 0.5 +/- 0.2; and TXB2, 1.2 +/- 0.4 ng/ml ELF). We also developed a protocol for the storage and subsequent analysis of BAL fluid that assures accurate and reproducible measurements of these eicosanoids. BAL samples stored for up to 8 months retain greater than 80% of their original eicosanoid content if the BAL fluid is immediately treated with methanol, concentrated, and stored at -70 degrees C without further purification. These data suggest that CF airways contain sufficient amounts of LTB4 both to recruit additional neutrophils into the airways and to stimulate neutrophils to release their injurious products. Therapies aimed at interfering with the production or action of LTB4 may be beneficial in CF and other lung diseases with a significant neutrophil response.

Sputum tumour necrosis factor-alpha and leukotriene concentrations in cystic fibrosis

It is postulated that a vigorous host inflammatory response in the cystic fibrosis lung contributes to lung injury. Tumour necrosis factor-alpha (TNF-alpha) may play a part in that process and in the generation of leukotrienes. Therefore, the relationships between sputum TNF-alpha, leukotriene concentration, and lung function abnormalities in 16 children with cystic fibrosis were investigated. Each subject provided sputum samples and performed spirometry. TNF-alpha was measured by enzyme linked immunosorbent assay; individual leukotrienes were separated using high performance liquid chromatography and quantified by radioimmunoassay. The geometric mean concentration of TNF-alpha was 129.7 pg/ml and 95% confidence interval 48.2 to 348.3. Mean (SEM) leukotriene B4 (LTB4) was 97.8 (22.9) pmol/g and total cysteinyl leukotrienes were 60.9 (14.8) pmol/g. Mean (SD) forced expiratory volume in one second (FEV1) of the group was 53 (15)% of predicted and forced vital capacity (FVC) was 65 (14)% of predicted. There was a significant positive correlation between TNF-alpha and both LTB4 and the total cysteinyl leukotriene sputum content. An inverse relationship existed between TNF-alpha and FEV1 and FVC. Moreover, a negative correlation was observed between sputum LTB4 and FEV1 and FVC. These results suggest that TNF-alpha and the leukotrienes may participate in the airways inflammation and airflow obstruction observed in cystic fibrosis subjects and support the hypothesis that TNF-alpha upregulates the 5-lipoxygenase pathway in vivo.

Decreased polymorphonuclear leucocyte chemotactic response to leukotriene B4 in cystic fibrosis

Evidence that leukotriene B4 (LTB4) is a significant inflammatory mediator in chronic pseudomonal respiratory disease was sought in adolescents and young adults with cystic fibrosis. Specific chemotaxis of peripheral blood polymorphonuclear leucocytes (PMN) was used as an indirect measure of remote in vivo exposure to LTB4. PMN from 17 patients showed a significant decrease in chemotaxis to 10(-7)-10(-9) M LTB4, but normal responses to 10(-8) M n-formyl-methionyl-leucyl-phenylalanine and 4 mg/ml casein, when compared with 17 healthy age- and sex-matched controls. This result is consistent with chronic production of LTB4, and specific deactivation of circulating PMN receptors for LTB4 in patients with cystic fibrosis. Pharmacologic inhibition of LTB4 production in vivo may help elucidate its role in the pathogenesis of lung damage in cystic fibrosis.

Enhanced synthesis of cysteinyl leukotrienes in psoriasis

Cysteinyl leukotriene synthesis was investigated in patients with psoriasis. A non-invasive test requiring no stimulation was employed by measuring the major index metabolite of LTC4, which appears in urine. The presence of this metabolite, LTE4, was shown unequivocally by gas chromatography-mass spectrometry. Routinely LTE4 was quantitated by specific radio immunoassay after its isolation by reversed-phase high-performance liquid chromatography. Furthermore, in representative samples amounts of LTE4 obtained by radioimmunoassay were validated by gas chromatography-mass spectrometry. We demonstrate a significant (p less than 0.01) more than fourfold increase of urinary LTE4 in psoriasis compared to healthy volunteers. Urinary LTE4 was log normally distributed with geometric mean values (95% confidence intervals) of 11 (9-14) nmol LTE4/mol creatinine in healthy volunteers (n = 11) and 51 (28-95) nmol LTE4/mol creatinine in psoriasis (n = 9). The present study shows that cysteinyl leukotriene synthesis is enhanced in patients with psoriasis and that measurement of urinary LTE4 is a useful parameter to monitor its rate of synthesis.

Effects of mucoid and non-mucoid Pseudomonas aeruginosa isolates from cystic fibrosis patients on inflammatory mediator release from human polymorphonuclear granulocytes and rat mast cells

Mucoid Pseudomonas aeruginosa causing chronic bronchopulmonary infection in cystic fibrosis (CF) patients may interfere with host defence mechanisms. We investigated 13 P. aeruginosa strains isolated from sputa of CF patients with regard to the induction or modulation of inflammatory mediator release from human neutrophils (PMN) and rat mast cells. The effects of mucoid as compared to non-mucoid bacteria were studied using a mucoid strain and its non-mucoid revertant. The release of leukotrienes (LT) and histamine in response to the majority of the CF strains was insignificant. However, preincubation of PMN with P. aeruginosa caused a dose-dependent decrease (50-95%) of LTB4 and LTC4 generation and LTB4 metabolism induced by the Ca(2+)-ionophore A23187 or opsonized zymosan (ZX) (P less than 0.001). The mucoid strains caused a three- to 10-fold higher impairment of LTB4 release (P less than 0.05) and a concomitant down-regulation of LTB4 receptors on neutrophils. Inhibitory effects were also obtained for mucoid and non-mucoid bacteria when the phorbol-ester or the Ca(2+)-ionophore induced luminol enhanced chemiluminescence response (P less than 0.001) or the histamine release from rat peritoneal mast cells (P less than 0.01) was studied. The bacteria-cell contact with non-mucoid strains was associated with an increased Ca2+ influx into PMN, whereas mucoid bacteria had no effect. In addition, a protein kinase C-dependent decrease of the C3bi receptor was suppressed by the mucoid--and less effectively--by the non-mucoid strain. The results suggest that the impairment of the phagocytic and inflammatory system may contribute to the pathogenesis and persistence of mucoid P. aeruginosa infection in CF.

Enzymic preparation of dioxygen-18 labelled leukotriene E4 and its use in quantitative gas chromatography-mass spectrometry

A simple and rapid method is described for the preparation of a stable isotope oxygen-18 labelled leukotriene E4 (LTE4). Oxygen-18 labelling of LTE4 methyl ester in oxygen-18 water catalysed by a pig liver esterase resulted in the incorporation of two oxygen-18 atoms in the carboxylic group of LTE4 to the extent of 89.8% ([18O2]LTE4) and one oxygen-18 atom to the extent of 9.4% ([16O18O]LTE4), with only 0.7% remaining unchanged ([16O2]LTE4). [18O2]LTE4 was found not to back-exchange following incubation in acidified urine (pH 4.0) at 4 degrees C for up to 20 h. [18O2]LTE4 was demonstrated to be a useful internal standard in a method for the quantitative determination of LTE4 in human urine involving high-performance liquid chromatography and gas chromatography with negative-ion chemical ionization tandem mass spectrometry: the concentration of LTE4 in a 24-h urine sample of a healthy subject was determined to be 68.1 pg/ml.

Sputum cysteinyl-leukotriene levels correlate with the severity of pulmonary disease in children with cystic fibrosis

Sputum samples from 13 children with cystic fibrosis (CF) were analyzed for leukotrienes (LTs) LTB4, LTC4, LTD4, and LTE4. Distribution of LTB4 appeared to be normal, and of cysteinyl-LTs log normal. Total cysteinyl-LT levels, of which on average 75% was LTE4, were nearly 10 times higher than in earlier studies. Log LTE4 and total cysteinyl-LT levels correlated with the overall severity of pulmonary disease assessed by Chrispin-Norman chest radiograph score (Log LTE4: r = 0.701, r2 = 49.1%, P = 0.008. Log total cysteinyl-LTs: r = 0.715, r2 = 51.1%, P = 0.006). There was no apparent relationship between LTB4 levels and Chrispin-Norman chest radiograph score, nor between the level of any of the LTs and age or organism cultured from sputum. These findings suggest that the cysteinyl-LTs may be involved in the pathophysiology of pulmonary disease in CF.