Leukotrienes (LTs) are known to act as a mediator provoking tissue response in inflammation. LTs, particularly type B4 (LTB4) as chemotactic factor of neutrophil are released from neutrophils and gastric mucosal cells when these cells are stimulated by Helicobacter pylori. The present study was performed to test a possibility that eupatilin may prevent the H. pylori-induced gastric cell damage by observing whether this chemical inhibit the release of LTB4 from H. pylori-stimulated gastric cells (Kato III) and neutrophils. As observed in the previous study, H. pylori induced the release of LTB4 from these cells and at the same influx of Ca2+ into the cells. In the presence of eupatilin, the release of LTB4 was inhibited whereas Ca2+ influx was not affected. Probably eupatilin may inhibit the release of LTB4 by preventing the synthesis of LTs. These results suggest that eupatilin can has a therapeutic effect on H. pylori-induced gasric cell damage.
Helicobacter pylori* ; Helicobacter* ; Inflammation ; Leukotriene B4* ; Leukotrienes ; Neutrophils*

It has been implicated that leukotrienes play roles in the pathogenesis of gastritis and gastric ulceration associated with Helicobacter pylori (H. pylori). Rebamipide is being used as an antiulcer drug but it's mechanism of action has not been understood well. One possible mechanism of action of this drug is to inhibit the cellular release of leukotrienes by various stimuli, particularly H. pylori. In the present study, attempts were made to test this possibility and the results are as follows. When Kato III cells (gastric adenoma cells) were stimulated by H. pylori, leukotriene D4 (LTD4) was released and rebamipide inhibited this release dose-dependently. Similar experiment was performed on neutrophils because the infilteration of neutrophils is a common phenomenon in H. pylori-infected gasrtric tissues. Neutrophils released LTD4 when these cells were stimulated by H. pylori and rebamipide also inhibited this release. Furthermore, rebamipide inhibited the release of LTD from neutrophils induced by calcium ionophore A23187 and arachidonic acid. The results suggest that rebamipide has the action to inhibit the release of LTD4 from various cells and this action may contribute in part to prevent the ulcerogenesis induced by H. pylori.
Adenoma ; Arachidonic Acid ; Calcimycin ; Calcium ; Gastritis ; Helicobacter pylori* ; Helicobacter* ; Leukotriene D4* ; Leukotrienes ; Neutrophils ; Stomach Ulcer

Cysteinyl leukotrienes (cys-LTs) are potent mediators of inflammation derived from arachidonic acid through the 5-lipoxygenase/leukotriene C4 synthase pathway. The derivation of their chemical structures and identification of their pharmacologic properties predated the cloning of their classical receptors and the development of drugs that modify their synthesis and actions. Recent studies have revealed unanticipated insights into the regulation of cys-LT synthesis, the function of the cys-LTs in innate and adaptive immunity and human disease, and the identification of a new receptor for the cys-LTs. This review highlights these studies and summarizes their potential pathobiologic and therapeutic implications.
Adaptive Immunity ; Arachidonate 5-Lipoxygenase ; Arachidonic Acid ; Asthma ; Clone Cells ; Cloning, Organism ; Humans ; Inflammation Mediators ; Leukotrienes*

Leukotrienes (LTs) are known to act as a mediator provoking tissue response in inflammation. This finding implicates that LTs also play important roles in the pathogenesis of H. pylori-induced gastritis and gastric ulceration. Rebamipide is being currently used as a therapeutics for gastritis and peptic ulcer, but their mechanisms of action have not been known clearly yet. One possibility is that their therapeutic effects are ascribed to interfering with the H. pylori-induced release of LTs from neutrophils and gastric mucosal cells. In the present study, this possibility was tested using LTB4 as the test material in human neutrophils and Kato III cells(gastric adenoma cells as a substitute for gastric mucosal cells). The release of LTB4 from both neutrophils and Kato III cells was time and H. pylori-dose dependent. The maximum release of LTB4 was induced by neutrophils and Kato III cells when these cells incubated with H. pylori 4.8 X 108 cells/ml for 30 min. But in the presence of rebamipide the release of LTB4 from these cells was suppressed in dose dependent manners. The release was completely suppressed at 1.0 mM of rebamipide in neutrophils and 2.0 mM of this drug in Kato III cells, respectively. We also obtained the results that the release of LTB4 was induced by A23187 (Ca2+ ionophore) and the A23187-induced release was also inhibited by rebamipide. It seems that the mechanism of action of rebamipide is through its interaction with the level of intracellular Ca2+. In view of the roles of LTB4 in inflammatory reaction and the roles of H. pylori in gastritis and peptic ulcer, the effects of this drug observed in this study may contribute to their therapeutic action in these gastric disorders.
Adenoma ; Calcimycin ; Gastritis ; Helicobacter pylori* ; Helicobacter* ; Humans ; Inflammation ; Leukotriene B4* ; Leukotrienes ; Neutrophils ; Peptic Ulcer ; Stomach Ulcer

Chronic spontaneous urticaria (CSU) is characterized by typically short-lived and fleeting wheals, angioedema or both, which occur spontaneously and persist for longer than 6 weeks. This term is applied to the most common subtype of chronic urticaria. The underlying pathophysiology for CSU involves mast cell and basophil degranulation with release of histamine, leukotrienes, prostaglandins and other inflammatory mediators. Although a variety of treatments exist, many patients do not tolerate or benefit from the existing therapies and even require more effective treatments. Omalizumab is currently the only licensed biologic for antihistamine-refractory CSU, and novel drugs are under development. This article reviews its current status regarding pathogenesis and approach to treatment as well as therapeutic agents that are under development for the treatment of CSU.
Angioedema ; Basophils ; Biological Products ; Histamine ; Humans ; Leukotrienes ; Mast Cells ; Omalizumab ; Prostaglandins ; Urticaria

Lipoxygenase is a protein with non-heme iron atom, which has been discovered in many animals and plants. Lipoxygenase which has a close relationship with human tumors, inflammatory diseases, asthma, arteriosclerosis, and toxic action of chemicals could not only di-oxygenate endogenous polyunsaturated fatty acid to yield bioactive factors such as leukotrienes(LTs), but also has co-oxidation activity to activate xenobiotics. Lipoxygenase inhibitors include hydroxamic acid derivatives, nordihydroguaiaretic acid, flavonoids, FLAP inhibitors and so on. All of them can effectively restrain the catalytic action of lipoxygenase. Literatures demonstrate that the inhibitors can block the formation of relevant bioactive factors and toxic products of xenobiotics clinically which are used to prevent and cure the relevant diseases to keep people healthy.
Animals ; Flavonoids ; pharmacology ; Humans ; Leukotrienes ; metabolism ; Lipoxygenase Inhibitors ; pharmacology ; Masoprocol ; pharmacology ; Oxidation-Reduction ; Xenobiotics ; metabolism

With the acceleration of aging society, delaying aging or promoting healthy aging has become a major demand for human health. 5-Lipoxygenase (5-LOX) is a key enzyme catalyzing arachidonic acid into leukotrienes (LTs), which is a potent mediator of the inflammatory response. Previous studies showed that abnormal activation of 5-LOX and overproduction of LTs are closely related to the occurrence and development of aging-related inflammatory diseases. Therefore, inhibiting 5-LOX activation is a possibly potential strategy for treating age-related diseases. In this paper, the latest research progress in 5-LOX activation, 5-LOX in mediating aging-related diseases and its small molecule inhibitors is briefly reviewed to provide scientific theoretical basis and new ideas for the prevention and treatment of aging-related inflammatory diseases.
Humans ; Arachidonate 5-Lipoxygenase ; Leukotrienes ; Arachidonic Acid ; Aging ; Lipoxygenase Inhibitors/pharmacology*

BACKGROUND AND OBJECTIVE: The cysteinyl leukotrienes are bioactive lipid mediators that contribute to the pathophysiologic condition of asthma and rhinosinusitis. We tested whether the leukotriene receptor antagonist ONO-1078 (Pranukast) had steroid sparing effect on mode- rate to severe asthmatics with chronic rhinosinusitis. METHODS: Eighteen asthmatic patients with chronic rhinosinusitis who required more than 800 mcg/day of budesonide inhalation for the adequate control of asthma symptoms were recruited for this study. For the first 4 weeks, patients were treated with high dose (800-1200 mcg/day) budesonide inhalation. For the next 4 weeks, the dose of budesonide inhalation was decreased by 400 mcg/day and oral ONO-1078 (900mg/day) was administered. FEV1 was evaluated every 2 weeks, and PC20 on methacholine challenge, serum eosinophil cationic protein and blood eosinophil count were measured every 4 weeks. Diary cards were completed with morning and evening PEFR and symptom scores for asthma and rhinosinusitis during the treatment periods. RESULTS: Despite the reduction of the dose of inhaled corticosteroid by 400mcg/day, FEV1 and PEFR did not decrease with the addition of oral ONO-1078. The symptom scores of asthma and rhino-sinusitis did not change, and the need for beta2-agonist did not increase. CONCLUSION: These results suggest that ONO-1078 might have steroid sparing effect in moderate to severe persistent asthmatics with chronic rhinosinusitis who required high dose nhaled budesonide to control asthma symptoms.
Asthma ; Budesonide ; Eosinophil Cationic Protein ; Eosinophils ; Humans ; Inhalation ; Leukotrienes ; Methacholine Chloride ; Peak Expiratory Flow Rate ; Receptors, Leukotriene

PURPOSE: Atopic dermatitis (AD) is a genetically determined, chronic relapsing skin disease. The pathogenesis of AD is complex and the course is unpredictable. Atopy is an important risk factor for the development of AD. Cysteinyl leukotrienes (Cys-LTs) were implicated in the pathophysiology of allergic diseases, and are being targeted for their diagnosis and treatments. Early detection of tissue inflammation of target organ is important to enable early prevention and management of allergic diseases. The aim of our study is to evaluate the differences in urinary leukotrienes E4 (LTE4) levels, according to AD symptom score and aeroallergen sensitization in children with AD by using noninvasive techniques. METHODS: We recruited 46 children with AD, using predetermined criteria. Clinical features of AD were evaluated by a physician, using scoring atopic dermatitis (SCORAD) index. Aeroallergen sensitization was measured by using a skin prick test and UniCap. Urine samples were also collected on day of the 1st and 2nd visits, and were analyzed for LTE4 with an enzyme-linked immunoassay kit. RESULTS: SCORAD indeces of children with AD were correlated with urinary LTE4 levels. Total immunoglobulin E (IgE) and eosinophil counts also had significant correlation with urinary LTE4 levels. Especially, aeroallergen sensitization of atopic AD significantly correlated with urinary LTE4 of these patients. CONCLUSION: Urinary LTE4 levels significantly correlated with serum total IgE and number of sensitized aeroallergen in children with AD. Clinical features of AD evaluated with SCORAD index related with urinary LTE4 level. Urinary LTE4 might be a valuable, noninvasive marker for different pathogenesis of AD.
Child ; Dermatitis, Atopic ; Eosinophils ; Humans ; Immunoassay ; Immunoglobulin E ; Immunoglobulins ; Inflammation ; Leukotriene E4 ; Leukotrienes ; Risk Factors ; Skin ; Skin Diseases

PURPOSE: Cysteinyl leukotrienes are important inflammatory mediators in the pathogenesis of asthma; therefore interruption of cysteinyl leukotrienes by leukotriene receptor antagonists improves clinical symptoms in the management of patients with mild to moderate asthma. We evaluated whether clinical response to montelukast, a leukotriene receptor antagonist, in childhood asthma was predicted by genotypes of leukotriene C4 synthase (LTC4S) promoter gene polymorphism. METHODS: An 8-week prospective, open trial of montelukast was carried out in 161 children with mild to moderate asthma. Genotyping of LTC4S gene polymorphism was determined by restriction fragment length polymorphism. RESULTS: The distribution of the LTC4S genotypes AA, AC, and CC was 70.8 percent, 23.6 percent, and 5.6 percent, respectively in asthma group and 74.0 percent, 22.6 percent, and 3.4 percent, respectively in control group. A statistically significant difference in the distribution of LTC4S genotype was not observed between the asthma and the control groups, and there was no significant difference between the LTC4S genotype and asthma severity. The responders to montelukast were significantly prevalent in the mild asthma group (P< 0.05). There was no significant difference in the distribution of the responders compared to non-responders within genotype in the total asthma group or the moderate asthma group. However, the responsiveness for montelukast was significant difference within genotype for both AA and AC/CC in the mild asthma group: The AA genotype was more included in the responder group (P< 0.05). CONCLUSION: In the mild persistent asthma group, the A allele of LTC4S polymorphism may be regarded as a predictable factor for clinical response to montelukast. However, LTC4S polymorphism was not significantly associated with the clinical response to montelukast in asthmatic children.
Alleles ; Asthma* ; Child ; Genotype ; Humans ; Leukotriene Antagonists ; Leukotriene C4* ; Leukotrienes ; Polymorphism, Restriction Fragment Length ; Prospective Studies ; Receptors, Leukotriene