Urinary Leukotriene E4 Excretion Research Articles

Urinary cysteinyl leukotrienes in one-year follow-up of percutaneous transluminal angioplasty for peripheral arterial occlusive disease

Background and aimsTreatment of severe peripheral arterial occlusive disease requires percutaneous revascularization. However, little is known about risk factors or predictors for reocclusion/restenosis. Cysteinyl leukotrienes are highly bioactive lipid mediators of inflammation. Their intravascular production may take place in the atheromatous plaque or result from interaction within activated leukocyte-platelet aggregates. MethodsWe prospectively measured urinary leukotriene E4, the main end-metabolite of cysteinyl leukotrienes in a group of 179 subjects with peripheral artery occlusive disease of the lower extremities. At the enrollment to the study, 22.9% had angioplasty and the remaining had angioplasty with stent implantation. During 12-month follow-up, 29.6% developed reocclusion/restenosis despite a standard pharmacotherapy. We evaluated treatment outcomes at 1, 3, 6 and 12-month follow-up visits, along with urinary leukotriene E4 excretion. ResultsDuring the study period, we observed a linear increase of urinary leukotriene E4 excretion only in subjects whose lower limb ischemia worsened. Moreover, elevated leukotriene E4 in urine was found only in subjects who developed reocclusion/restenosis. This was significant not only as a coincidence at the time of the follow-up visit, but leukotriene E4 elevation preceded clinical manifestation of reocclusion/restenosis. ConclusionsOur results demonstrated that serial measurements of urinary leukotriene E4 allowed to predict failure of angioplasty with/or without stent implantation for peripheral artery occlusive disease. However, to prove causality between cysteinyl leukotrienes overproduction and occlusive lower limb ischemia, a clinical trial with leukotrienes modifying drugs would be required.

Diagnostic Utility of Urinary LTE4 in Asthma, Allergic Rhinitis, Chronic Rhinosinusitis, Nasal Polyps, and Aspirin Sensitivity

Urinary leukotriene E4 (LTE4) is a well-validated marker of the cysteinyl leukotriene pathway, and LTE4 elevation has been described in conditions such as asthma, aspirin sensitivity, and chronic rhinosinusitis (CRS). There have been a number of reports investigating the role of spot urine LTE4 to predict aspirin sensitivity; however, variability in urinary LTE4 may affect the accuracy of this approach. Here, we explored the utility of 24-hour urinary LTE4 in 5 clinical diagnoses of allergic rhinitis, asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), CRS without nasal polyps, and aspirin sensitivity. This was a retrospective review of patients who had 24-hour quantification of urinary LTE4 by a clinically validated liquid chromatography tandem mass spectrometry method and their assigned diagnoses after assessment and clinical care. Twenty-four-hour urinary LTE4 elevations were seen in those with asthma and those with CRSwNP but influenced by underlying aspirin sensitivity. Elevation in LTE4 was significant in those with CRSwNP after adjusting for aspirin sensitivity. Allergic rhinitis was not associated with elevated LTE4 excretion. Receiver operator characteristic analysis of 24-hour urinary LTE4 showed that a cutoff value of 166 pg/mg Cr suggested the presence of history of aspirin sensitivity with 89% specificity, whereas a cutoff value of 241 pg/mg Cr discriminated "challenge-confirmed" aspirin-sensitive subjects with 92% specificity. Elevated 24-hour excretion of urinary LTE4 is a reliable and simple test to identify aspirin sensitivity in patients with respiratory diagnoses.

Elevated levels of leukotriene C4 synthase mRNA distinguish a subpopulation of eosinophilic oesophagitis patients

Cysteinyl leukotrienes contribute to Th2-type inflammatory immune responses. Their levels in oesophageal tissue, however, do not distinguish patients with eosinophilic oesophagitis (EoE) from controls. We asked whether mRNA levels of leukotriene C4 synthase (LTC4 S), a key regulator of leukotriene production, could serve as a marker for EoE. Digital mRNA expression profiling (nCounter(®) Technology) was performed on proximal and distal oesophageal biopsies of 30 paediatric EoE patients and 40 non-EoE controls. Expression data were confirmed with RT-qPCR. LTC4 S mRNA levels were quantified in whole blood samples. Leukotriene E4 was measured in urine. LTC4 S mRNA levels were elevated in proximal (2.6-fold, P < 0.001) and distal (2.9-fold, P < 0.001) oesophageal biopsies from EoE patients. Importantly, increased LTC4 S mRNA transcripts identified a subpopulation of EoE patients (28%). This patient subgroup had higher serum IgE levels (669 U/mL vs. 106 U/mL, P = 0.01), higher mRNA transcript numbers of thymic stromal lymphopoietin (TSLP) (1.6-fold, P = 0.009) and CD4 (1.4-fold, P = 0.04) but lower IL-23 mRNA levels (0.5-fold, P = 0.04). In contrast, elevated levels of IL-23 mRNA were found in oesophageal biopsies of patients with reflux oesophagitis. LTC4 S mRNA transcripts in whole blood and urinary excretion of leukotriene E4 were similar in EoE patient subgroups and non-EoE patients. Elevated oesophageal expression of LTC4 S mRNA is found in a subgroup of EoE patients, concomitant with higher serum IgE levels and an oesophageal transcriptome indicative of a more-pronounced allergic phenotype. Together with TSLP and IL-23 mRNA levels, oesophageal LTC4 S mRNA may facilitate diagnosis of an EoE subpopulation for personalized therapy.

Pharmacodynamics, pharmacokinetics and safety of GSK2190915, a novel oral anti‐inflammatory 5‐lipoxygenase‐activating protein inhibitor

To assess the pharmacokinetics, pharmacodynamics, safety and tolerability of the 5-lipoxygenase-activating protein inhibitor, GSK2190915, after oral dosing in two independent phase I studies, one in Western European and one in Japanese subjects, utilizing different formulations. Western European subjects received single (50-1000 mg) or multiple (10-450 mg) oral doses of GSK2190915 or placebo in a dose-escalating manner. Japanese subjects received three of four GSK2190915 doses (10-200 mg) plus placebo once in a four period crossover design. Blood samples were collected for GSK2190915 concentrations and blood and urine were collected to measure leukotriene B₄ and leukotriene E₄, respectively, as pharmacodynamic markers of drug activity. There was no clear difference in adverse events between placebo and active drug-treated subjects in either study. Maximum plasma concentrations of GSK2190915 and area under the curve increased in a dose-related manner and mean half-life values ranged from 16-34 h. Dose-dependent inhibition of blood leukotriene B₄ production was observed and near complete inhibition of urinary leukotriene E₄ excretion was shown at all doses except the lowest dose. The EC₅₀ values for inhibition of LTB₄ were 85 nM and 89 nM in the Western European and Japanese studies, respectively. GSK2190915 is well-tolerated with pharmacokinetics and pharmacodynamics in Western European and Japanese subjects that support once daily dosing for 24 h inhibition of leukotrienes. Doses of ≥50 mg show near complete inhibition of urinary leukotriene E₄ at 24 h post-dose, whereas doses of ≥150 mg are required for 24 h inhibition of blood LTB₄.

Incidence of aspirin hypersensitivity in patients with chronic rhinosinusitis and diagnostic value of urinary leukotriene E4

Chronic rhinosinusitis (CRS) with nasal polyposis (NP) may be associated with hypersensitivity to nonsteroidal anti-inflammatory drugs, representing a syndrome of aspirin-exacerbated respiratory disease (AERD). The aim of the study was to validate a simple measurement of urinary leukotriene E4 (uLTE4) excretion for the diagnosis of AERD in patients with CRS and indication for surgery. Subjects requiring functional endoscopic sinus surgery (FESS) were recruited from the Department of Otolaryngology (n = 24). Before surgery, a standard oral placebo-controlled aspirin challenge was performed to diagnose aspirin hypersensitivity. Urine samples were collected on the placebo day and both before and within 2 to 4 hours after aspirin challenge for uLTE4 measurement. All patients with CRS had sinusitis confirmed by computed tomography. Previous ear, nose, and throat surgery was performed in 70% of the patients, NP was present in 86%, and asthma was diagnosed in 62.5%. AERD was diagnosed in 8 subjects (7 women and 1 man). Five of those patients had bronchoconstriction. At baseline, median uLTE4 was 7.5-times higher in AERD subjects than in the remaining patients. It increased almost 6-fold following the challenge, while remained unchanged in patients without aspirin hypersensitivity. Pretest uLTE4 had a sensitivity of 87.5% and specificity of 93.75% to diagnose aspirin hypersensitivity in patients with CRS. After the challenge, the values improved to 100% sensitivity and 93% specificity. Among CRS subjects requiring FESS, as many as 33.3% may have AERD and respond to a small provocative dose of aspirin with bronchoconstriction and/or mucosal and skin edema. A simple and inexpensive measurement of uLTE4 can help diagnose AERD in patients with CRS with sensitivity of 87.5%, but its specificity is limited and depends on the arbitrary threshold of uLTE4.

Effect of Sodium Cromoglycate on Mast Cell Mediators during Hyperpnea in Athletes

The role of mast cells in the airway response to exercise and the benefit of sodium cromoglycate (SCG) in athletes are unclear. The purpose of this study was to clarify the role of mast cell mediators in the airway response to exercise in athletes and to investigate the effect of SCG. Eleven athletes with exercise-induced bronchoconstriction (EIB+) and 11 without (EIB-) performed a eucapnic voluntary hyperpnea (EVH) test (a surrogate for exercise) 10 min after inhalation of a placebo or 40 mg of the mast cell stabilizing agent sodium cromoglycate. The urinary concentrations of 9a,11β-PGF2 (a metabolite of PGD2 and a marker of mast cell activation) and leukotriene E4 (LTE4) were measured by enzyme immunoassay 60 min before and for 90 min after the challenge. In the EIB+ group, the maximum fall in forced expiratory volume in 1 s (FEV1) of 20.3% ± 3% on placebo was reduced to 11.5% ± 1.9% after SCG (P = 0.003). There was an increase in the urinary excretion of 9α,11β-PGF2 on the placebo day after EVH in both groups (P < 0.05) that was abolished by SCG. In the EIB+ group, there was also an increase of urinary LTE4 on the placebo day that was abolished by SCG, whereas the urinary excretion of LTE4 was inconsistent in the EIB- group. The results support mast cell activation with release of bronchoconstrictive mediators after hyperpnea in athletes with and without EIB and inhibition by SCG. The degree of airway responsiveness to the specific mediator released is likely to determine whether or not bronchoconstriction will occur after EVH.

Urinary leukotriene E4 excretion: A biomarker of inflammatory bowel disease activity

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory disorders collectively referred to as inflammatory bowel diseases (IBD). Cysteinyl leukotrienes are proinflammatory 5-lipoxygenase-derived products that play a major role in the immune and inflammatory response. Consequently, they may be involved in the pathogenesis of IBD. The aim of this study was therefore to evaluate 1) the urinary excretion of leukotriene E(4) (LTE(4)) in IBD patients and healthy volunteers, and 2) the association between LTE(4) production and the activity (relapse/remission) of the disease. IBD patients and healthy volunteers were prospectively recruited. CD and UC activity was determined on inclusion with the Crohn's Disease Activity Index and Clinical Activity Index, respectively. Urine was collected and the urinary excretion of LTE(4) was measured by liquid chromatography tandem mass spectrometry. 32 CD patients, 28 UC patients, and 30 controls were enrolled in the study. LTE(4) urinary excretion was significantly increased (P < 0.01) in CD [52.0 pg/mg creatinine (10th-90th percentiles: 26.2-148.0)] and UC [64.1 pg/mg creatinine (10th-90th percentiles: 26.7-178.0)] patients compared to controls [32.3 pg/mg creatinine (10th-90th percentiles: 21.8-58.8)]. LTE(4) levels were higher (P < 0.001) in patients with active disease than in patients in remission, for whom the levels of LTE(4) were similar to the levels of controls. Cysteinyl leukotriene pathway activation could contribute to the inflammation associated with IBD. The quantification of urinary LTE(4) could be an interesting noninvasive biomarker for the assessment of IBD activity.

Clinical studies of asthma phenotypes focusing on the role of leukotrienes

AbstractIntroduction: Inflammation in the airways in connection to asthma is complex and the mechanisms underlying the associated clinical symptoms involve the interaction of many different kinds of cells and mediators, giving rise to different phenotypes.Objective: The objective of the present thesis was to investigate the molecular and cellular mechanisms that result in two of these phenotypes, i.e. aspirin‐intolerant asthma (AIA) and allergic asthma. The main focus was on leukotrienes.Materials and Methods: (i) Thirty‐three subjects with diagnosed AIA were challenged with celecoxib, a selective inhibitor of cyclooxygenase (COX)‐2. (ii) With the ultimate objective of finding a marker that could be used to identify patients with leukotriene‐associated asthma, the capacity to produce leukotrienes and the responsiveness to inhaled leukotrienes were determined in 20 subjects with mild asthma and in 10 healthy control individuals. (iii) Eight individuals with mild allergic asthma were challenged repeatedly with low doses of allergen in an experimental model aimed at mimicking the natural exposure to allergen. Exhaled nitric oxide was measured throughout the study. (iv) Thirteen patients with allergic asthma were subjected to bronchial challenges with methacholine and leukotriene D4 (LTD4) prior to and after administration of 500‐µg fluticasone twice daily for 2 weeks, and their levels of exhaled nitric oxide and urinary leukotriene E4 (LTE4) were determined.Results: (i) Both escalating doses from 5–100 mg (administered in a blinded, placebo‐controlled study) and an open‐label challenge with 200 + 200 mg celecoxib were tolerated well by AIA individuals. (ii) Neither group exhibited a correlation between the formation of leukotriene B4 by their whole blood in response to ex vivo stimulation or urinary levels of LTE4 and airway responsiveness to LTD4. (iii) The level of nitric oxide in the air that they exhaled rose significantly. At the same time, these subjects did not report any symptoms of asthma, did not require rescue by bronchodilator medication, and did not display any change in the calibre of their airways. (iv) Inhalation of glucocorticoid attenuated the responsiveness to methacholine and reduced the level of exhaled nitric oxide, but neither the responsiveness to LTD4 nor urinary excretion of LTE4 was affected.Conclusions: (i) This finding indicates that the intolerance reaction leading to broncho‐constriction in patients with AIA is caused by inhibition of COX‐1 and, furthermore, provides a scientific basis for administration of selective inhibitors of COX‐2 to alleviate prostaglandin‐mediated pain and inflammation in these patients. (ii) In further attempts to predict which asthmatic patients will respond well to anti‐leukotriene treatment, investigations on the capacity for leukotriene synthesis, responsiveness to these agents and expression of their specific receptors in the lungs are being performed. (iii) Monitoring of exhaled nitric oxide on a daily basis may allow for early detection of exacerbation in subjects with allergic asthma. (iv) Neither the release nor the actions of leukotrienes appear to be sensitive to inhaled glucocorticoids, strengthening the rationale for using a combination of glucocorticosteroids and anti‐leukotrienes to treat allergic asthma.

Leukotriene Receptor Blockade Does Not Prevent Acute Mountain Sickness Induced by Normobaric Hypoxia

Previous research has demonstrated that blood and urine concentrations of various leukotrienes are elevated with acute hypoxic exposure. Some of these studies have suggested that leukotrienes may be mediators in the pathogenesis of acute mountain sickness (AMS). We conducted a randomized, double-blind study to determine if AMS symptoms correlated with the increase in leukotriene synthesis and if prophylactic leukotriene receptor blockade would prevent the development of AMS in a simulated high altitude exposure. Three male and five female subjects completed two normobaric hypoxia chamber exposures (average F(IO2) 12.4 +/- 0.09%), receiving montelukast 10 mg daily for 4 days prior to one session and placebo for 4 days prior to the other session. There were no differences in Lake Louise AMS scores, time spent in the chamber, average oxygen saturation, and average heart rate during the montelukast and placebo sessions. Headache scores were higher during treatment with montelukast than during treatment with placebo. Compared to preexposure values, urinary leukotriene E4 concentrations were unchanged during the hypoxic chamber exposure following treatment with placebo or montelukast. Urinary leukotriene E4 excretion during the hypoxic exposure did not differ between the two sessions. A 4-day course of leukotriene receptor blockade does not prevent symptoms of AMS. These results suggest that leukotrienes do not play a causal role in the pathophysiology of AMS.

Abstracts

Abstracts

Urinary inflammatory mediators and inhalation of hypertonic saline in children

The inflammatory mechanisms of hypertonic saline-induced bronchoconstriction are not well understood. Seventeen asthmatics with (n=11) and without bronchial hyperresponsiveness (BHR) (n=6) and 18 randomly selected nonatopic nonasthmatic controls without BHR were evaluated by urine samples collected before and 1 h after hypertonic saline provocation test. Histamine, 11beta-PGF2alpha, and LTE4 were analysed by enzyme immunoassay (EIA) and eosinophil protein X (EPX) by radioimmunoassay (RIA). The levels of leukotriene E4 (LTE4) increased significantly after the challenge tests, both in the asthmatics (median: 354 pg/mg pre-challenge vs. 628 pg/mg post-challenge; P=0.05) and in the controls (median: 294 pg/mg pre-challenge vs. 460 pg/mg post-challenge; P <0.01). The levels of histamine also increased significantly in the latter (median: 299 micromol/mg pre-challenge vs. 569 micromol/mg post-challenge; P=0.03). However, the levels of 11beta-PGF2alpha and EPX did not change significantly after the challenge tests either in the asthmatics or in the controls. The inhalation of hypertonic saline increased urinary excretion of LTE4 both in the asthmatics and in the controls. The slight increase of leukotrienes was enough to induce airway obstruction in some of the asthmatics, because of the hyperresponsiveness in their airways.

Tacrolimus reduces urinary excretion of leukotriene E4 and inhibits aspirin-induced asthma to threshold dose of aspirin

The exact mechanism of aspirin-induced asthma is not clear. It has been postulated that precipitation of asthma attacks by aspirin is linked to inhibition of COX activity and massive release of cysteinyl leukotriene into the airway. Tacrolimus, a macrolide-derived immunosuppressant, is used for immunosuppression in organ transplantation and also for allergic diseases such as atopic dermatitis. We evaluated the effects of tacrolimus in aspirin-induced asthma by using a double-blind, crossover study design. Twelve patients with aspirin-induced asthma (male:female, 3:9; mean age +/- SD, 36.7 +/- 7.2 years) received either tacrolimus (0.1 mg/kg) or placebo 2 hours before the threshold dose of oral aspirin. In the placebo arm, oral aspirin significantly decreased FEV 1 concomitant with significant increases in sputum eosinophilic cationic protein and urinary leukotriene E(4) levels. Tacrolimus significantly inhibited bronchoconstriction and abrogated aspirin-induced increase in both sputum eosinophilic cationic protein and urinary leukotriene E(4) levels. The current study suggested that tacrolimus inhibited bronchoconstriction to a threshold dose of aspirin by inhibition of cysteinyl leukotriene excretion.

Macrolides in the treatment of asthma and cystic fibrosis

Asthma and cystic fibrosis are two respiratory diseases characterized by chronic inflammation, leading to remodelling of the airways. Macrolides are widely used antibiotics, with a peculiar anti-inflammatory effect. On the basis of the methodologies used by the Cochrane collaboration, this review discusses the evidence for their long-term use as anti-inflammatory agents in these two diseases. Three randomized-controlled trials (RCTs) were identified for both asthma and cystic fibrosis. A positive effect of macrolides on reducing eosinophil numbers and markers of eosinophilic inflammation was demonstrated in patients with asthma. Data on cystic fibrosis demonstrated an effect on lung function with an increase of 5.4% in forced vital capacity (FVC) in patients treated with macrolide vs. placebo, but without a significant effect on FEV1. Side-effects were rare, mild and reversible on withdrawal of treatment. Although preliminary data from small studies are promising, the role of macrolides in the treatment of these chronic disorders needs to be more firmly established with larger, well-designed trials, targeted to investigate major clinical outcomes.

Clinical features of asthmatic patients with increased urinary leukotriene E4 excretion (hyperleukotrienuria): Involvement of chronic hyperplastic rhinosinusitis with nasal polyposis

Background The urinary leukotriene E4 (U-LTE4) concentration is significantly increased in patients with aspirin-intolerant asthma (AIA). However, the relationship between the clinicopathogenetic factors of asthma and the U-LTE4 concentration remains undetermined. Objective We sought to examine the clinical features of asthmatic patients with increased excretion levels of U-LTE4 (hyperleukotrienuria). Methods We measured the U-LTE4 concentrations in 137 asthmatic patients (including 64 patients with AIA) who were in clinically stable condition. A U-LTE4 concentration of 150 pg/mg creatinine or greater (mean U-LTE4 + 3 SDs of normal healthy control subjects) was indicative of hyperleukotrienuria. Results The basal concentration of U-LTE4 was significantly higher in the patients with AIA than in those with aspirin-tolerant asthma (ATA; median, 227.2 vs 90.3 pg/mg creatinine; P < .01). Compared with normal leukotrienuria in the patients with AIA, hyperleukotrienuria in the patients with AIA was associated with older age and decrease in pulmonary function. On the other hand, compared with normal leukotrienuria in the patients with ATA, hyperleukotrienuria in the patients with ATA was associated with severe asthma and chronic hyperplastic rhinosinusitis with nasal polyposis (CHRS/NP), which are well-known symptoms of the aspirin triad, as well as hypereosinophilia and anosmia. The patients with ATA with CHRS/NP excreted U-LTE4 at significantly high concentrations. There were significant decreases in the U-LTE4 concentrations before and after the sinus surgery in both the AIA and ATA groups ( P < .05). Conclusion Cysteinyl leukotrienes are not strictly associated with aspirin intolerance itself but rather with clinical features, such as CHRS/NP, that are similar to those seen in AIA. CHRS/NP might be involved in cysteinyl leukotriene overproduction in asthmatic patients.

Biochemical and clinical evidence that aspirin-intolerant asthmatic subjects tolerate the cyclooxygenase 2-selective analgetic drug celecoxib

Background: Subjects with aspirin-intolerant asthma (AIA) respond with bronchoconstriction and extrapulmonary adverse reactions to conventional nonsteroidal anti-inflammatory drugs (NSAIDs) that inhibit the cyclooxygenase (COX) step in the biosynthesis of prostaglandins. Recently, 2 isotypes of COX have been identified, and COX-2-selective NSAIDs have been developed for treatment of inflammatory disorders. Objective: We investigated whether 33 subjects with a typical history of AIA tolerated the new COX-2-selective NSAID celecoxib. Methods: All subjects displayed current aspirin sensitivity in oral or inhalation challenge tests. The subjects first underwent a double-blind, randomized, cross-over, increasing-dose challenge with placebo or celecoxib (10, 30, or 100 mg in suspension) on 2 occasions 7 days apart. Thereafter, all subjects were exposed to 400 mg of celecoxib administered during an open challenge session as two 200-mg doses 2 hours apart. Lung function, clinical symptoms, and urinary excretion of leukotriene E4 (LTE4) were monitored, with the latter being a sensitive biochemical marker of aspirin intolerance. Results: There were no changes in lung function or extrapulmonary symptoms during the double-blind sessions or in urinary excretion of LTE4. Also, the highest recommended daily dose of celecoxib was well tolerated, with no symptoms, lung function changes, or alterations in urinary LTE4 levels. Conclusions: A group of subjects with clinically well-documented AIA tolerated acute challenge with the selective COX-2 inhibitor celecoxib. The findings indicate that the intolerance reaction in AIA is due to inhibition of COX-1. Large long-term studies of COX-2 inhibitors in AIA should be undertaken. (J Allergy Clin Immunol 2003;111:1116-21.)

Role of cysteinyl leukotrienes in adenosine 5`-monophosphate induced bronchoconstriction in asthma

Background: Adenosine induced bronchoconstriction in patients with asthma is thought to be mediated by the synthesis and release of autacoids from airway mast cells. In vitro, adenosine induced constriction of...

INCREASED URINARY LEUKOTRIENE E4 AND EOSINOPHIL PROTEIN X EXCRETION IN PATIENTS WITH INTERSTITIAL CYSTITIS

The role of cysteinyl containing leukotriene C4, D4 and E4, and eosinophil protein X in interstitial cystitis is unknown. Leukotriene E4, the end product of cysteinyl containing leukotrienes, and eosinophil protein X are markers of the activation of mast cells and eosinophils, respectively. Cysteinyl containing leukotrienes are potent and specific chemoattractants for eosinophils. We compared the urinary excretion of leukotriene E4 and eosinophil protein X in patients with interstitial cystitis and in healthy controls. Morning spot urine samples from nine patients with interstitial cystitis who fulfilled National Institute of Diabetes and Digestive and Kidney Diseases criteria were collected on the day of cystoscopy with biopsies. Aliquots of urine specimens were immediately centrifuged and the supernatants were stored at -80C until use. Urine samples from 9 healthy women served as controls. Urinary leukotriene E4 and eosinophil protein X were measured by enzyme immunoassay and radioimmunoassay, respectively. All determinations were performed in duplicate and normalized to urine creatinine. Leukotriene E4 and eosinophil protein X were significantly increased in the morning urine of patients with interstitial cystitis compared with controls. The mean urinary excretion of leukotriene E4 plus or minus standard deviation was 148.8 +/- 62.5 and 62.2 +/- 17.5 ng./mmol. creatinine in patients and controls (p = 0.003), while the mean urinary excretion of eosinophil protein X was 109.7 +/- 70.4 and 43.7 +/- 22.0 microg./mmol. creatinine, respectively (p = 0.01). All urine cultures were negative. The mean mast cell count in detrusor biopsies in the interstitial cystitis group was 41 cells per mm.2 (range 5 to 84). Eosinophilic granulocytes were occasionally observed in the submucosa but not in the detrusor. Our study shows that patients with interstitial cystitis and detrusor mastocytosis have increased urinary leukotriene E4 and eosinophil protein X. It is possible that cysteinyl containing leukotrienes and eosinophil protein X are involved in the pathogenesis of interstitial cystitis. Urinary leukotriene E4 and eosinophil protein X may be useful markers for assessing the grade of activation of mast cells and eosinophils in patients with interstitial cystitis and/or for confirming the diagnosis. However, it remains to be investigated whether the increase in urinary leukotriene E4 and eosinophil protein X correlates with interstitial cystitis symptoms.

Urinary Leukotriene E4 Excretion During the First Month of Life and Subsequent Bronchopulmonary Dysplasia in Premature Infants

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. 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. Prospective, blinded, controlled study. Neonatal ICUs of a tertiary-care university hospital. 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. 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. 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.

Safety of a specific COX‐2 inhibitor in aspirin‐induced asthma

In a subset of patients with asthma, aspirin and several other non-steroidal anti-inflammatory drugs (NSAID) that inhibit simultaneously cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) precipitate dangerous asthmatic attacks. We tested the hypothesis that in patients with aspirin-induced asthma the attacks are triggered by inhibition of COX-1 and not COX-2. In twelve asthmatic patients (seven men, five women, average age 39 years) oral aspirin challenge precipitated symptoms of bronchial obstruction with fall in FEV1 > 20%, and a rise in urinary leukotriene E4 (LTE4) excretion; also in five patients the stable metabolite of PGD2, 9alpha11betaPGF2, increased in urine. The patients then entered a double-blind, placebo-controlled, cross-over study in which they received either placebo or rofecoxib in increasing doses 1.5-25.0 mg for 5 consecutive days, separated by a 1-week wash-out period. No patient on rofecoxib developed dyspnoea or fall in FEV1 > 20%; mean urinary LTE4 and 9alpha11betaPGF2 urinary levels, measured on each study day for 6 h post-dosing, remained unchanged. Two patients on placebo experienced moderate dyspnoea without alterations in urinary metabolites excretion. At least 2 weeks after completion of the study, all patients received on an open basis 25 mg rofecoxib without any adverse effects. NSAID that inhibit COX-1, but not COX-2, trigger asthmatic attacks in patients with asthma and aspirin intolerance. Rofecoxib can be administered to patients with aspirin-induced asthma.

Urinary excretion of leukotriene E4 and eosinophil protein X in children with atopic asthma.

Measurement of leukotriene E4 (LTE4) in urine is a noninvasive method for assessing changes in the rate of total body cysteinyl leukotriene production. Eosinophil protein X (EPX) has been used to assess eosinophil activity and monitor inflammation in bronchial asthma. The aim of the study was to look for differences in urinary LTE4 and EPX concentrations between children with stable atopic asthma and healthy controls and to compare asthmatic children with different disease severity. In addition the relationship was evaluated between urinary LTE4 and EPX levels and lung function. LTE4 was also measured (enzyme immunoassay) together with EPX (radioimmunoassay) in urine and lung function tests were carried out in children with mild asthma (steroid-naive) (n=49), moderate to severe asthma (using inhaled steroids) (n=31) and healthy control subjects (n=28). Urinary leukotriene E4 (LTE4) was significantly higher in children with asthma than in controls (median [25-75 percentile] 238.5 (126.5-375.7) SD 191.8 versus 189 (51-253.2) SD 131.7 pg.mg(-1) creatinine; p=0.021). Urinary EPX was also significantly increased in asthmatic children compared with controls (85.5 [64-131.5] SD 76.2 versus 48.5 [43.2-90] 112.1 microg x mmol(-1) creatinine; p=0.006). There were no differences in urinary LTE4 and EPX between the group of mild and the group of moderate to severe asthmatic children. There were significant associations between the urinary LTE4 and intrathoracic gas volume (ITGV), residual volume (RV), forced expiratory volume in one second (FEV1), forced expiratory capacity (FVC) and maximum expiratory flow rate at 25% of vital capacity (MEF25). Urinary EPX was only correlated with maximum expiratory flow rate at 75% of vital capacity (MEF75). Thus measurement of urinary LTE4 may predict the degree of airflow obstruction in asthmatic children. Urinary LTE4 and EPX are useful markers of airway inflammation and can be helpful in guiding asthma management. There was no correlation between LTE4 and EPX levels.