Leukotriene Levels Research Articles

Diagnostic value of serum cysteine leukotriene levels for obstructive sleep apnea hypopnea syndrome in children

Objective To assess the clinical value of the measurement of cysteine leukotriene (CysLTs) concentration in serum as a diagnostic predictor to screen the obstructive sleep apnea hypopnea syndrome (OSAHS) in children. Methods Serum CysLTs concentration was measured with ELISA kit in 75 patients with snoring before performing polysomnography (PSG). Subsequently, all the subjects underwent PSG test.Forty-one subjects were diagnosed as OSAHS, and 34 subjects didn't have OSAHS.These 34 non-OSAHS subjects were served as control group.Among the OSAHS group, 25 subjects were the Han nationality and 12 subjects were the Uyghur nationality.According to apnea hyponea index(AHI), the OSAHS group was divided into 3 groups, which were light, moderate and severe groups.And the serum CysLTs level of the OSAHS group was taken for correlation analysis with the sleep respiratory parameters.Compared with the PSG results, the clinical value of the measurement of CysLTs concentration in serum was taken as a diagnostic predictor to screen patients with OSAHS in children. Results 1.The serum CysLTs level of OSAHS group [(683.102±89.825) ng/L] was significantly higher than that in the control group [(461.985± 84.951) ng/L] (P<0.05). And it was correlated positively with AHI, longest apnea time, sleep apnea low aeration time (r=0.417, 0.422, 0.208, all P<0.05), but correlated negatively with the lowest oxygen saturation and the mean oxygen saturation (r=-0.192, -0.255, all P< 0.05).2.The serum CysLTs level [(773.118±92.015) ng/L] in severe OSAHS group was significantly higher than that in the moderate OSAHS group[(712.144±41.331) ng/L](P<0.05), and much more significantly higher than that in the light OSAHS group [(642.206±77.250) ng/L](P<0.05).3.When the serum CysLTs level was 560.872 ng/L, there was the best critical point with the highest sensitivity rate (92.7%) and specificity rate (94.1%), and the lowest misdiagnosis rate and the false dismissal rate, as diagnose accordance rate was 93.3%.4.The serum CysLTs level of Han [(704.417±77.149) ng/L] was higher than that of Uygur [(628.053±105.443) ng/L], and there was significant difference between the 2 groups (P<0.05). Conclusions Serum CysLTs level is closely related with the severity of OSAHS.There is difference in serum CysLTs level between different nationalities.The serum CysLTs level of the Han nationality is higher than the Uygur nationality.The serum level of CysLTs may be used as a predictor in screening OSAHS children and a biological marker of the severity of OSAHS children. Key words: Sleep apnea hypopnea syndrome, obstructive; Serum cysteine leukotriene; Child

Wasp venom allergy: effect of anti-IgE antibody on wasp venom anaphylaxis in a mouse model

Although anti-IgE antibody (Ab) therapy was recently shown to be effective in patients with bronchial asthma, no study has reported the effect of IgE therapy in the prevention of wasp venom anaphylaxis. In this study, we used a mouse model of wasp venom allergy to investigate the effect of anti-IgE Ab on wasp venom anaphylaxis. We developed a mouse model of wasp venom allergy by intraperitoneally (i.p.) injecting wasp venom into BALB/c mice twice on experimental day (day) 0 and 7. On day 20, a group of mice received an i.p. injection of mouse anti-IgE Ab as a pretreatment, and another group received rat anti-IgG1 Ab. On day 21, the animals were challenged by i.p. injection of wasp venom, and 30 min later, body temperature was measured and serum levels of leukotriene (LT) B4 and LTC4 were determined using enzyme immunoassay. The body temperature of mice treated with anti-IgE Ab and controls before and after wasp venom challenge was 37.8±0.2 vs 37.7± 0.3°C before challenge and 37.8±0.2 vs 37.1± 0.3°C after challenge, respectively, showing that anti-IgE Ab treatment significantly prevented body temperature from falling (p <0.05). Furthermore, anti-IgE Ab treatment reduced total serum IgE levels in the treated mice (42.2±15.9 pg/ml), compared with controls (105.9±23.1 pg/ml, p <0.05), and inhibited the secretion of LTC4 in the treated mice (32.0±18.8 pg/ml), but not in the controls (162.4±12.4 pg/ml, p <0.05), following challenge with wasp venom. The results of the present study indicate that anti-IgE Ab treatment is an effective preventive measure against wasp venom-induced anaphylaxis.

The antimicrobial peptide LL‐37 induces synthesis and release of cysteinyl leukotrienes from human eosinophils – implications for asthma

Eosinophils and their products, including leukotrienes and eosinophil cationic protein (ECP), are well-known mediators of inflammation and tissue damage in asthma. The antimicrobial peptide LL-37 exhibits a variety of immunomodulatory activities. However, the role of LL-37 in asthma has not been fully addressed. Here, we aim to investigate the effect of LL-37 on inducing inflammatory mediators in human eosinophils, probe the underlying mechanisms, and search for a clinical correlate. Primary eosinophils were isolated from peripheral blood. Leukotriene and ECP levels were measured using EIAs or ELISAs. Activation of leukotriene-synthesizing enzymes and signaling kinases was analyzed by Western blot or immunofluorescent imaging. LL-37/its proform hCAP18 expression was analyzed by Western blot. LL-37, via formyl peptide receptor-2 (FPR-2), triggered the release of cysteinyl leukotrienes (cys-LTs) from eosinophils. The release was more prominent in cells primed with the eosinophilopoietic cytokine GM-CSF or IL-5 or cells from asthmatic patients. LL-37 stimulates lipid body formation and activates cys-LT-synthesizing enzymes by multiple mechanisms: enhancing cPLA(2) activity by pERK1/2-mediated phosphorylation and inducing intracellular translocation and assembly of 5-LO and LTC(4) S at perinuclear locations and lipid bodies. In addition to cys-LTs, LL-37 enhances ECP release from eosinophils via pERK1/2. The expression of hCAP18 and its release following leukotriene stimulation are significantly higher in eosinophils from asthmatics. This study identifies LL-37 as an eosinophil-activating peptide that triggers release of inflammatory mediators. The clinical correlation suggests that LL-37/hCAP18 and its signaling pathway represent potential therapeutic targets for this disease.

Relationship between exhaled leukotriene and 8-isoprostane levels and asthma severity, asthma control level, and asthma control test score

ObjectiveExhaled breath condensate (EBC) is a completely non-invasive method for the collection of airway secretions to measure intense inflammation in the airways of asthmatics. It has been shown that the childhood asthma control test (c-ACT) is a good tool for use in the evaluation of asthmatics. Whether the c-ACT score and asthma control level correlate with the airway inflammation is not well known. We aimed to evaluate the relationship between exhaled cysteinyl leukotrienes (Cys-LTs) and 8-isoprostane levels and asthma severity, asthma control level and c-ACT score in asthmatic children. MethodsThirty asthmatic children were evaluated with c-ACT score and pulmonary function tests. Asthma severity and asthma control level were assessed according to GINA. EBC was collected and Cys-LTs and 8-isoprostane concentrations were determined using a specific immunoassay kit. ResultsExhaled 8-isoprostane level in patients with moderate persistent asthma [114 (55–146)pg/ml] was higher than in the mild persistent group [52 (21–91)pg/ml] (p=0.05, Mann–Whitney U [MWU]). EBC 8-isoprostane in children with 1–4 asthma exacerbations/year [52 (16–80)pg/ml] was significantly lower than in children with >4 asthma exacerbations/year [114 (57–129)pg/ml] (p<0.05, MWU). No significant relation was determined between exhaled 8-isoprostane and Cys-LTs levels and c-ACT score and asthma control level. Exhaled 8-isoprostane correlated negatively with bronchodilator response (p=0.015, r=−0.45). ConclusionsExhaled 8-isoprostane, as an oxidative stress specifier, was found to be increased in relation with asthma exacerbation frequency and oxidative stress increases with the severity of asthma. In contrast to asthma severity level, c-ACT score and asthma control level may not reflect airway inflammation.

The leukotriene receptor antagonist montelukast and aortic stenosis

Aortic stenosis shares several characteristics with atherosclerotic lesions, such as inflammation and lipid accumulation leading to extensive calcification of the valvular leaflets, which eventually causes the aortic valve to narrow [1]. However, lipid lowering drugs of the statin class have not been shown to retard the progression of aortic stenosis. In fact, to date there is no medical treatment for this valvular heart disease and aortic stenosis remains the most common indication for surgical valve replacement [1]. Recently, the leukotriene pathway was shown to be associated with aortic stenosis. Local leukotriene production in calcified human valves increased reactive oxygen species production, activated osteogenic pathways and stimulated calcification [2]. In addition, the expression levels of leukotriene synthesizing enzymes within aortic valves were significantly correlated with the severity of aortic stenosis, as determined by echocardiography [2]. Leukotriene receptor antagonists (LTRA) are a well-established treatment of asthma. In addition, we recently showed that the therapeutic potential of anti-leukotriene drugs may go beyond asthma, based on the observation that the LTRA montelukast was associated with a decreased risk for recurrent cardiovascular events, such as stroke and myocardial infarction [3]. Taken together, these observations suggested that LTRAs may be protective for the development of aortic stenosis. To test this hypothesis, we have analyzed the incidence of aortic stenosis in relation to the use of montelukast. In brief, a nationwide population-based cohort of approximately 7 million Swedish residents integrating data from the Prescribed Drug, Patient, Cause of Death, Income, Educational and Emigration Registers was followed from July 1 2005, to December 31 2008. The cohort and statistical methods have been described in detail in our previous studies [3, 4]. Analyses were performed in the whole adult population after exclusion of subjects with a prior diagnosis of aortic valve disease (ICD-10 code I35; ICD-9 code 4241; ICD-8 code 3659 and 4241). Montelukast exposure was defined from the national Swedish Prescribed Drug Register as claimed prescriptions of Anatomical Therapeutical Chemical (ATC) code R03DC03. Calculated from each dispense date, subjects were considered exposed for 3 months based on a prescription length of 3 months of use. Aortic stenosis (ICD-10 codes I35.0 and I35.2) was monitored as outcome and defined according to either the primary diagnosis or the primary cause of death, as recorded in the Patient and Cause of Death Registers. The associations between montelukast use and outcome were examined by Cox proportional hazard models estimating the hazard ratio (HR) of drug use, after adjustment for age, gender and socioeconomic factors (education level and income), the presence of respiratory disease and the use of drugs for respiratory and cardiovascular disease, as previously described [3] and detailed in supplementary Table S1. The prevalence of aortic valve disease in the whole population was 0.25% at baseline. Montelukast use was associated with a trend of decreased incidence of aortic stenosis, which did not reach statistical significance (Table 1). Table 1 Fully adjusted* hazard ratio (HR) with 95% confidence interval (95% CI) for aortic stenosis with montelukast (non-use was used as reference level) Several limitations of the present study should be acknowledged. The 3.5 years of exposure data available in the present study is relatively short given that aortic stenosis develops over a longer time. It can also not be excluded that previously exposed subjects may have been considered as unexposed, and that recently commenced montelukast treatment may not yet have affected the development of aortic stenosis. In addition, using the diagnosis code as outcome will not define the severity of aortic stenosis and will miss asymptomatic cases not seeking hospital care. The latter limitations can drive the association towards the null due to lower statistical power. Finally, in these national registry data, we are not able to adjust completely for all possible confounding factors. However, the most plausible confounders have been taken into account by adjustment for gender, age, socioeconomic status as well as cardiovascular and respiratory diagnoses and treatments. In summary, mechanistic studies have implicated the leukotriene pathway in aortic stenosis. Although the present study did not show a significant association of montelukast use with aortic stenosis, the results suggested a trend towards beneficial effects. However, the non-randomized, observational design of the present study means that no causality can be definitely attributed and that the association could be driven by unmeasured confounding. More importantly, the present study indicates a safety of anti-leukotriene drugs in the context of aortic stenosis. The latter finding is an important piece of information for the design of interventional studies targeting the leukotriene pathway in aortic stenosis.

Exploration of bioactivity in traditionally used medicinal plants

Arachidonic acid (AA) is metabolized in the body through two main metabolic pathways with the enzymes: cyclooxygenases (COX) and lipoxygenases (LOX). Elevated levels of prostanoids and leukotrienes, products of the two respective pathways, have been linked to inflammatory diseases as well as to early stages of carcinogenesis. Finding a dual inhibitor of COX and LOX is promising in preventing the inflammation and diseases that are linked to the overproduction of both pathways while minimizing the side effects associated with inhibition of individual pathways.

Insulin-containing lipogenic stimuli suppress mast cell degranulation potential and up-regulate lipid body biogenesis and eicosanoid secretion in a PPARγ-independent manner

Lipid bodies are most studied in adipocytes, where the lipogenic action of insulin initiates their formation. Here, we test the hypothesis that insulin may regulate lipid body content in mast cells and hence, modify their proinflammatory potential. Our data show that insulin causes lipid body accumulation in RBL2H3 and BMMCs. Lipid body accumulation in mast cells is associated with enhanced levels of leukotriene-synthesizing enzymes (LTC4S and 5-LO). Increased basal and antigen-stimulated release of LTC4 is observed in insulin-treated mast cells. Concomitantly, the insulin-containing lipogenic stimulus induces a phenotypic change in mast cells, where this enhancement in leukotriene levels is accompanied by a marked down-regulation in secretory granule content and release in response to stimulus. Mast cells exposed to insulin exhibit altered scatter and fluorescence properties, accumulating in a SSC(lo)FSC(hi) population that exhibits decreased BS staining and degranulation responses and is enriched in NR-positive lipid bodies and eicosanoid synthesis enzymes. Lipid body accumulation in mast cells is mechanistically distinct from the process in adipocytes; for example, it is independent of PPARγ up-regulation and does not involve significant accumulation of conjugated glycerides. Thus, chronic exposure to metabolic stimuli, such as insulin, may be a determinant of the proinflammatory potential of the mast cell.

Effect of leukotriene inhibitors on evolution of experimental brain contusions

Leukotriene levels increase in cerebrospinal fluid (CSF) following controlled cortical impact (CCI) injury in rats. We investigated the impact of two different leukotriene inhibitors in the CCI model on CSF leukotriene levels, brain water content (BWC), brain swelling (BS) contusion size and cellular response. 134 male Sprague Dawley rats were investigated at 4, 24 and 72 h after CCI for CSF leukotriene levels and BWC/BS, lesion size in T2-weighted magnetic resonance imaging and immunohistochemistry. Animals received vehicle, MK-886, an inhibitor of 5-lipoxygenase activating protein, or Boscari(®) , a mixture of boswellic acids, acting as competitive nonredox 5-lipoxygenase inhibitors before trauma and then every 8 h until sacrifice. The intracranial pressure (ICP) was unaffected by treatment. Boscari treatment reduced CSF leukotriene C4 increase by -45% at 4 h (P < 0.03) and increase of BWC and BS by 49% (P < 0.05) and -58% at 24 h. Treatment with both substances showed a reduction of lesion volume at 72 h by -21% (P < 0.01) in T(2) -weighted magnetic resonance imaging, which was reflected in a smaller lesion area determined from a NeuN labelled section (-17% to -20%, P < 0.05). Triple immunofluorescence and Fluoro-Jade B staining showed rarefaction of neurones, glia and vasculature in the contusion core, whereas in the pericontusional zone astro- and microglia were upregulated in the presence of dying neurones. Treatment resulted in an improved survival of NeuN labelled neurones in the pericontusional cortex (+15% to +20%, P < 0.05). Leukotriene inhibition should be further investigated as therapeutic option to counteract secondary growth of traumatic brain contusions and to possibly improve pericontusional neuronal survival.

Eosinophil-derived leukotriene C4 signals via type 2 cysteinyl leukotriene receptor to promote skin fibrosis in a mouse model of atopic dermatitis

Atopic dermatitis (AD) skin lesions exhibit epidermal and dermal thickening, eosinophil infiltration, and increased levels of the cysteinyl leukotriene (cys-LT) leukotriene C(4) (LTC(4)). Epicutaneous sensitization with ovalbumin of WT mice but not ΔdblGATA mice, the latter of which lack eosinophils, caused skin thickening, collagen deposition, and increased mRNA expression of the cys-LT generating enzyme LTC(4) synthase (LTC(4)S). Skin thickening and collagen deposition were significantly reduced in ovalbumin-sensitized skin of LTC(4)S-deficient and type 2 cys-LT receptor (CysLT(2)R)-deficient mice but not type 1 cys-LT receptor (CysLT(1)R)-deficient mice. Adoptive transfer of bone marrow-derived eosinophils from WT but not LTC(4)S-deficient mice restored skin thickening and collagen deposition in epicutaneous-sensitized skin of ΔdblGATA recipients. LTC(4) stimulation caused increased collagen synthesis by human skin fibroblasts, which was blocked by CysLT(2)R antagonism but not CysLT(1)R antagonism. Furthermore, LTC(4) stimulated skin fibroblasts to secrete factors that elicit keratinocyte proliferation. These findings establish a role for eosinophil-derived cys-LTs and the CysLT(2)R in the hyperkeratosis and fibrosis of allergic skin inflammation. Strategies that block eosinophil infiltration, cys-LT production, or the CysLT(2)R might be useful in the treatment of AD.

Epithelial regulation of eicosanoid production in asthma

Alterations in the airway epithelium have been associated with the development of asthma in elite athletes and in subjects that are susceptible to exercise-induced bronchoconstriction (EIB). The syndrome of EIB refers to acute airflow obstruction that is triggered by a period of physical exertion. Asthmatics who are susceptible to EIB have increased levels of cysteinyl leukotrienes (CysLTs, i.e., LTs C4, D4, and E4) in induced sputum and exhaled breath condensate, and greater shedding of epithelial cells into the airway lumen. Exercise challenge in individuals susceptible to this disorder initiates a sustained increase in CysLTs in the airways, and secreted mucin release and smooth muscle constriction, which may be mediated in part through activation of sensory nerves. We have identified a secreted phospholipase A2 (sPLA2) with increased levels in the airways of patients with EIB called sPLA2 group X (sPLA2-X). We have found that sPLA2-X is strongly expressed in the airway epithelium in asthma. Further, we discovered that transglutaminase 2 (TGM2) is expressed at increased levels in asthma and serves as a regulator of sPLA2-X. Finally, we demonstrated that sPLA2-X acts on target cells such as eosinophils to initiate cellular eicosanoid synthesis. Collectively, these studies identify a novel mechanism linking the airway epithelium to the production of inflammatory eicosanoids by leukocytes.

Transglutaminase 2 Knock-out Protects Against Airway Inflammation And Tissue Remodeling In Ova-specific Allergic Asthma In Mice

Transglutaminase 2 (TGase 2) is over-expressed in a variety of inflammatory diseases including allergic asthma. TGase 2 inhibitors block TGase 2 over-expression. This study aimed to investigate whether TGase 2-/- protects against airway inflammation and tissue remodeling associated with OVA-induced allergic asthma in mice. C57BL/6 or TGase 2-/- mice were sensitized and challenged with OVA to induce asthma. OVA-specific serum IgE and leukotrienes (LTs) levels were measured by ELISA, and the recruitment of inflammatory cells into BAL fluid or lung tissues was stained with Diff-Quik and H & E, goblet cell hyperplasia by PAS.

RCT of Montelukast as Prophylaxis for Upper Respiratory Tract Infections in Children

Infections with viruses causing upper respiratory tract infection (URI) are associated with increased leukotriene levels in the upper airways. Montelukast, a selective leukotriene-receptor antagonist, is an effective treatment of asthma and allergic rhinitis. To determine whether prophylactic treatment with montelukast reduces the incidence and severity of URI in children. A randomized, double-blind, placebo-controlled study was performed in 3 primary care pediatric ambulatory clinics in Israel. Healthy children aged 1 to 5 years were randomly assigned in a 1:1 ratio to receive 12-week treatment with 4 mg oral montelukast or look-alike placebo. Patients were excluded if they had a previous history of reactive airway disease. A study coordinator contacted the parents by phone once a week to obtain information regarding the occurrence of acute respiratory episodes. The parents received a diary card to record any acute symptoms of URI. The primary outcome measure was the number of URI episodes. Three hundred children were recruited and randomly assigned into montelukast (n = 153) or placebo (n = 147) groups. One hundred thirty-one (85.6%) of the children treated with montelukast and 129 (87.7%) of the children treated with placebo completed 12 weeks of treatment. The number of weeks in which URI was reported was 30.4% in children treated with montelukast and 30.7% in children treated with placebo. There was no significant difference in any of the secondary variables between the groups. In preschool-aged children, 12-week treatment with montelukast, compared with placebo, did not reduce the incidence of URI.

Preliminary Results of a Phase II Trial of Montelukast for the Treatment of Bronchiolitis Obliterans Syndrome After HSCT

Bronchiolitis obliterans syndrome (BOS) after allogeneic HSCT is a deadly manifestation of cGVHD. Current treatments are inferior and yield transient responses with published overall survival of 44% at 2 years. Although the pathogenesis of BOS after HSCT is unknown, a similar disease, BOS after lung transplant is associated with elevated leukotriene levels. We present preliminary results from a prospective, open label, phase II trial testing the efficacy of montelukast, a leukotriene inhibitor, for the treatment of BOS after HSCT. BOS diagnostic criteria included: FEV1<75%, FEV1/VC < 0.7 or air trapping on CT and RV>120% or RV/TLC>120% in the absence of infection and presence of another cGVHD manifestation. Subjects had stable or declining FEV1 on stable or decreasing immunosuppression. Twenty patients have been enrolled. One withdrew prior to treatment and one withdrew after study medication initiation; 16/20 patients have reached the primary endpoint (6 months) on study medication (10 mg qhs). Study participants age ranged from 15-64 years, 12/20 female, with baseline FEV1 from 24 to 73% predicted. All patients met criteria for response on the clinical trial with less than 15% decline in FEV1 % predicted at the primary endpoint. FEV1 increased 5-13% predicted in 5 participants, remained stable in 6 (change <5%), and declined 5-13% in 5. Comparison of patient pre-study FEV1 decline to on-study FEV1 values was generated using the slope of FEV1 volume vs. days post-transplant. The difference in pre- and primary endpoint slope revealed: 14/16 improvement and 2/16 decline. Six minute walk test demonstrated that 4/16 patients had significant increases in walk distance that exceeded the minimally important difference, 2 of which had declining FEV1%. 2/20 had a significant decline in walk test accompanied by a decline in FEV1% predicted. Of 10 patients eligible for the 2 year endpoint, 7/10 are alive with 2 patients with durable FEV1 improvements from baseline (FEV1+ 6%, +14%), 2 stable (FEV1 0%, +1%), 3 with decline from baseline (FEV1 -4%, -4%, -8%). Montelukast was well-tolerated with only one grade II probable attributable adverse event (insomnia) during the six-month collection period. These findings suggest that montelukast is a promising therapy for BOS after allogeneic HSCT.

The Protective Effect of Eupatilin against Hydrogen Peroxide-Induced Injury Involving 5-Lipoxygenase in Feline Esophageal Epithelial Cells

In this study, we focused to identify whether eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone), an extract from Artemisia argyi folium, prevents H2O2-induced injury of cultured feline esophageal epithelial cells. Cell viability was measured by the conventional MTT reduction assay. Western blot analysis was performed to investigate the expression of 5-lipoxygenase by H2O2 treatment in the absence and presence of inhibitors. When cells were exposed to 600 µM H2O2 for 24 hours, cell viability was decreased to 40%. However, when cells were pretreated with 25~150 µM eupatilin for 12 hours, viability was significantly restored in a concentration-dependent manner. H2O2-treated cells were shown to express 5-lipoxygenase, whereas the cells pretreated with eupatilin exhibited reduction in the expression of 5-lipoxygenase. The H2O2-induced increase of 5-lipoxygenase expression was prevented by SB202190, SP600125, or NAC. We further demonstrated that the level of leukotriene B4 (LTB4) was also reduced by eupatilin, SB202190, SP600125, NAC, or nordihydroguaiaretic acid (a lipoxygenase inhibitor) pretreatment. H2O2 induced the activation of p38MAPK and JNK, this activation was inhibited by eupatilin. These results indicate that eupatilin may reduce H2O2-induced cytotoxicity, and 5-lipoxygenase expression and LTB4 production by controlling the p38 MAPK and JNK signaling pathways through antioxidative action in feline esophageal epithelial cells.

Exhaled eicosanoids and biomarkers of oxidative stress in exacerbation of chronic obstructive pulmonary disease

IntroductionEicosanoids and oxidants play an important role in inflammation, but their role in chronic obstructive pulmonary disease (COPD) is uncertain. In this study we hypothesized that levels of exhaled leukotrienes, prostaglandins and biomarkers of oxidative stress are increased in infectious exacerbations of COPD and that they decrease after antibiotic therapy.Material and methodsCysteinyl-leukotrienes (LTs), leukotriene B4 (LTB4), prostaglandin E4, hydrogen peroxide (H2O2) and 8-isoprostane were measured in exhaled breath condensate (EBC) in 16 COPD patients with infectious exacerbations (mean age 64 ±12 years, 13 male) on day 1, during antibiotic therapy (days 2-4), 2-4 days after therapy and at a follow-up visit when stable (21-28 days after therapy).ResultsThere was a significant fall in concentration of cys-LTs, LTB4 and 8-isoprostane at visit 3 compared to day 1 (cys-LTs: 196.5 ±38.4 pg/ml vs. 50.1 ±8.2 pg/ml, p < 0.002; LTB4: 153.6 ±25.5 pg/ml vs. 71.9 ±11.3 pg/ml, p < 0.05; 8-isoprostane: 121.4 ±14.6 pg/ml vs. 56.1 ±5.2 pg/ml, p < 0.03, respectively). Exhaled H2O2 was higher on day 1 compared to that at visits 2 and 3 (0.74 ±0.046 µM vs. 0.52 ±0.028 µM and 0.35 ±0.029 µM, p < 0.01 and p < 0.01, respectively). Exhaled PGE2 levels did not change during exacerbations of COPD. Exhaled eicosanoids and H2O2 in EBC measured at the follow-up visit (stable COPD) were significantly higher compared to those from healthy subjects.ConclusionsWe conclude that eicosanoids and oxidants are increased in infectious exacerbations of COPD. They are also elevated in the airways of stable COPD patients compared to healthy subjects.

Effect of combined chemotherapy and anti-inflammatory drugs on murine schistosomiasis.

Hepatic granulomas resulting from Schistosoma mansoni infection contain high levels of prostaglandins (PG) and leukotrienes. The present experimental study was conducted to show the effect of murine S. mansoni infection on PGE2 level in the liver granuloma homogenate and to explore the possibility of using non-steroidal anti-inflammatory drugs (NSAIDs) namely, ibuprofen (CAS 15687-27-1) and naproxen (CAS 22204-53-1), either alone or in combination with praziquantel (CAS 55268-74-1) to induce regression of hepatic morbidity or to ameliorate the biochemical and histopathological consequences and intensity of infection. Infection with S. mansoni increased the level of alanine amino-transaminase (ALT), gamma glutamyl transferase (GGT), PGE2, hepatic collagen deposition, antibody titre and circulating schistosomal antigen. The last parameter was reduced significantly by progression of infection in the 11th and 16th weeks. Treatment with praziquantel was found to reduce the number of worms (97%), with complete absence of immature ova and increase in the number of dead ova. Also it reduced all the elevated parameters except PGE2. NSAIDs were found to reduce significantly the level of PGE2 at 9 weeks but not at 11 and 16 weeks post-infection. ALT and GGT were not significantly decreased compared to their corresponding controls. Treatment with ibuprofen or naproxen either alone or in combination with praziquantel or praziquantel alone reduced significantly the granuloma diameters. Collagen deposition and percentage of fibrotic area were significantly decreased compared to infected control but the antibody titre or circulating antigen levels were not affected. Combined therapy of praziquantel with ibuprofen or naproxen improved most of the parameters estimated and maintained the reducing effect on PGE2 at 11 and 16 weeks post-infection. So it can be concluded that in S. mansoni infection treatment with ibuprofen or naproxen is not preferable without treatment of schistosomiasis by using praziquantel.

Premenstrual asthma and leukotriene variations in the menstrual cycle

Several authors have reported an increase in leukotriene C4 in the premenstrual phase in women with severe premenstrual asthma, indicating that antileukotrienes could be used in treatment. To analyse the role of leukotrienes in premenstrual asthma. A questionnaire on respiratory symptoms and peak flow during one complete menstrual cycle was given to women of fertile age to define them as asthmatics who suffered from premenstrual asthma or not. Premenstrual asthma (PMA) was defined as a clinical or functional deterioration (≥20%) in the premenstrual phase compared with the preovulatory phase. Blood samples to measure leukotriene C4 were taken during the preovulatory and premenstrual phases. Blood samples were taken in 62 asthmatic women, 34 of whom (54.3%) presented PMA criteria, all with a premenstrual deterioration of between 20 and 40%. There was no difference in leukotriene C4 levels between the preovulatory and premenstrual phases in the women who suffered from PMA (1.50ng/mL vs. 1.31ng/mL; p=0.32) and those who did not (1.40ng/mL vs. 1.29ng/mL; p=0.62). Neither were there any differences in leukotriene levels between women with or without PMA. The results were similar for each category of asthma severity. Our data show that leukotriene C4 does not appear to be involved in the pathogenesis of premenstrual asthma, or support the use of anti-leukotrienes in the specific treatment of premenstrual asthma, at least in women with a moderate premenstrual deterioration. No differences appeared in any of the categories of asthma severity.

Glycyrrhetinic acid prevents cutaneous scratching behavior in mice elicited by substance P or PAR-2 agonist

Although glycyrrhetinic acid (GA) has been used for the prevention of itch in chronic dermatitis, the mechanism underlying the antipruritic effects of GA is still unclear. Recently, several mediators other than histamine, such as substance P and tryptase, were found to participate in chronic itch. Here, we investigated the effect of GA on pruritus induced by various pruritic agents including histamine in mice. We also determined the level of leukotriene (LT)B(4) in mouse skin injected with substance P in an effort to uncover part of the antipruritic mechanism of GA. Scratching events were counted for 10 min after intradermal injection of histamine, substance P (100 nmol per site each), protease-activated receptor-2 (PAR-2) agonistic peptide (50 nmol per site), or LTB(4) (0.03 nmol per site) with or without GA (4 nmol per site) into male ICR mice. Levels of LTB(4) in the skin after injection of substance P were determined by ELISA. GA did not suppress scratching behavior induced by histamine and LTB(4), but markedly and dose-dependently suppressed that induced by substance P and PAR-2 agonistic peptide. LTB(4) levels in skin elevated by substance P were lowered by GA. These data support the efficacy of GA in counteracting itch in chronic dermatitis because GA reduced scratching behavior induced by substance P and PAR-2 agonistic peptide. GA may exert antipruritic effects via inhibition of LTB(4) production in skin.

Urinary Leukotriene E4, Obesity, and Adenotonsillar Hypertrophy in Chinese Children with Sleep Disordered Breathing

Sleep disordered breathing (SDB) has been associated with increased inflammatory responses. Changes in the level of pro-inflammatory leukotrienes (LTs) may initiate or exacerbate pediatric SDB and may play a major role in end-organ morbidity. The objective of the study was to investigate the relationship of LT productions with severity of SDB, obesity, and adenotonsillar hypertrophy in children. Prospective, observational study that included standard questionnaires, physical examinations, overnight polysomnography (PSG), and urinary leukotriene E(4) (LTE(4)) assay. Sleep Center and Laboratory of Nutriology. 282 children with SDB and 94 healthy control subjects were recruited. Urinary LTE(4) levels were elevated in children with SDB compared to the controls, and LTE(4) productions emerged disease severity- and obesity-dependent increases. In stepwise multiple regression analysis, the independent predictors of the apnea-hypopnea index (AHI) included LTE(4) level and adenotonsillar-size sum score (P < 0.001 respectively; adjusted R(2)=0.318). A positive relationship between LTE(4) urinary level and adenotonsillar-size sum scores was present in the underweight/normal weight SDB subjects (r=0.276; P < 0.001), but not in the overweight/obese children (P > 0.05). Systemic inflammation mediated by LTs participates in the pathophysiological mechanisms of SDB in children. The magnitude of inflammation as reflected by urinary LTE(4) is significantly related to the severity of SDB and obesity. However, a correlation between LTE(4) concentration and adenotonsillar size is present only among nonobese children.

Determination of cysteinyl leukotrienes in exhaled breath condensate: Method combining immunoseparation with LC–ESI-MS/MS

A rapid and precise method for the identification and quantification of cysteinyl leukotrienes (leukotriene C 4, leukotriene D 4 and leukotriene E 4), essential markers of bronchial asthma, in exhaled breath condensate was developed. The protocol consists of immunoaffinity separation and a detection step, liquid chromatography combined with electrospray ionization tandem mass spectrometry (LC–ESI-MS/MS). In particular, the selected reaction monitoring mode was used for its extremely high degree of selectivity and the stable-isotope-dilution assay for its high precision of quantification. The developed method was characterized with a high precision (≤7.7%, determined as RSD), an acceptable accuracy (90.4–93.7%, determined as recovery), a low limit of detection (≤2 pg/ml EBC) and a low limit of quantification (≤10 pg/ml EBC). It was compared to other simple, clinically appropriate combinations of pre-treatment methods (solid phase extraction and lyophilization) with LC/MS. Finally, the method (a combination of immunoaffinity separation with LC–MS) was successfully tested in a clinical study where a significant difference was found in the concentration levels of cysteinyl leukotrienes between patients with occupational bronchial asthma and healthy subjects.