Release Of Leukotrienes Research Articles

Anti-nociceptive effect of seed extract of Acacia tortilis in rodents

Background: Management of pain is a primary clinical concern for any pathology in medical field. Addiction liability of opioids and troublesome gastrointestinal side effects of NSAIDs leads to intensive research for compound with lesser side effects.The aim of the study to evaluate the anti-nociceptive activity of Acacia Tortilis Seed Extract (ATE) in experimental animals.Methods: First of all, animals were randomly allocated into four groups of six animals each. In acetic acid induced writhing test model, Group I (NC) served as vehicle control received saline/Tween 80 0.1%, 10ml/kg BW orally, group II (ATE-100) and III (ATE-200) received ATE in dose of 100 and 200mg/kg BW orally respectively and group IV received the standard drug diclofenac sodium in dose of 50 mg/kg BW orally. Group I to IV were same in rest of three experimental models. One additional group of standard drugs (group V) morphine sulfate in dose of 5 mg/kg BW subcutaneously (SC) was allocated for screening method hot plate and tail flick tests. In Formalin induced paw licking test, three additional groups (group V) morphine sulfate in dose of 5mg/kg BW SC, group VI- morphine+naloxone (5mg/kg SC +2mg/kg intra-peritoneally (IP) and group VII - ATE+ naloxone (200mg/kg BW orally +2mg/kg BW IP) were also made.Results: The ATE when administered orally in dose of 100 and 200mg/ kg body weight (BW), produced significant analgesic activity (P <0.01) in acetic acid induced writhing syndrome and late phase of formalin test. In the hot plate test in mice and tail flick test in rats, ATE in same doses also showed significant analgesic activity (P <0.05) which is almost equally efficacious to standard drug diclofenac sodium (50mg/kg BW orally) but far less efficacious than morphine sulfate (5mg/kg BW subcutaneous).ATE (200mg/Kg BW orally) activity did not blocked by naloxone (2mg/kg intra-peritoneal).Conclusions: ATE possesss significant anti-nociceptive activity as evidenced in all the animal models of nociception. It might exert its effect through the peripheral mechanism of analgesic action possibly by interference in biosynthesis, release and/or action of prostaglandins and leukotrienes.

The effect of n-3 fatty acids and coenzyme Q10 supplementation on neutrophil leukotrienes, mediators of inflammation resolution and myeloperoxidase in chronic kidney disease

BackgroundNeutrophils release leukotriene (LT)B4 and myeloperoxidase (MPO) that may be important mediators of chronic inflammation in chronic kidney disease (CKD). The n-3 fatty acids (n-3 FA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have the potential to attenuate inflammation through production of LTB5 and the Specialized Proresolving Lipid Mediators (SPM) that promote the resolution of inflammation. In animal models, coenzyme Q10 (CoQ) also attenuates inflammation by reducing MPO and LTB4. ObjectiveThis study evaluated the independent and combined effects of n-3 FA and CoQ supplementation on neutrophil leukotrienes, the pro-inflammatory eicosanoid 5-hydroxyeicosatetraenoic acid (5-HETE), SPM, and plasma MPO, in patients with CKD. DesignIn a double-blind, placebo-controlled intervention of factorial design, 85 patients with CKD were randomized to either n-3 FA (4 g), CoQ (200 mg), both supplements, or control (4 g olive oil), daily for 8 weeks. Plasma MPO and calcium ionophore-stimulated neutrophil release of LTs, 5-HETE and SPM were measured at baseline and after 8 weeks. ResultsSeventy four patients completed the intervention. n-3 FA, but not CoQ, significantly increased neutrophil LTB5 (P < 0.0001) and the SPM 18-hydroxyeicosapentaenoic acid (18-HEPE), resolvin E1 (RvE1), resolvin E2 (RvE2) and resolvin E3 (RvE3) that derive from EPA, as well as 17-hydroxydocosahexaenoic acid (17-HDHA) and resolvin D5 (RvD5) that derive from DHA (all P < 0.01). Neutrophil LTB4 and its metabolites, and 5-HETE were not significantly altered by n-3 FA or CoQ. Plasma MPO was significantly reduced with n-3 FA alone (P = 0.013) but not when given in combination with CoQ. Conclusionn-3 FA supplementation in patients with CKD leads to increased neutrophil release of LTB5 and several SPM, as well as a reduction in plasma MPO that may have important implications for limiting chronic inflammation.

Comparative evaluation of the efficacy of topical amlexanox 5% oral paste and triamcinolone acetonide 0.1% oral paste in the treatment of Recurrent Aphthous Stomatitis (RAS)

Background: A double-blind randomized control trial was conducted to compare the clinical efficacy of topical triamcinolone acetonide 0.1% and amlexanox 5% in recurrent apthous stomatitis (minor). Materials and Methods: Forty adult patients were assessed for erythema, ulcer size, pain scores, and ulcer healing on three evaluation visits within 24 h of ulcer formation, third day, and fifth day. All participants were monitored for compliance with treatment protocols of four times daily application of calibrated quantity of medication. Results and Discussion: Ninety percent of controls when compared with 65% of the participants in the amlexanox group showed complete improvement of peri-ulcer erythema. Pain reduction was marked from the first to the fifth day (F = 15.249, P = 0.000). The control participants showed 90% reduction in pain in comparison to 70% in the amlexanox group. The mean ulcer size was shown to reduce from the first to fifth day in both groups (F = 18.611, P = 0.000). Completely healed ulcers were seen in 70% of the participants in the control group compared with 75% of the participants in the amlexanox group. Conclusion: The data suggest that the clinical efficacy of topical amlexanox 5% is comparable to topical 0.1% triamcinolone acetonide and may be considered a substitute except in pain control, which was marginally less for the treatment for recurrent apthous stomatitis (minor).

Evidence for autocrine and paracrine regulation of allergen-induced mast cell mediator release in the guinea pig airways

Mast cells play an essential role in immediate type hypersensitivity reactions and in chronic allergic diseases of the airways, including asthma. Mast cell mediator release can be modulated by locally released autacoids and circulating hormones, but surprisingly little is known about the autocrine effects of mediators released upon mast cell activation. We thus set out to characterize the autocrine and paracrine effects of mast cell mediators on mast cell activation in the guinea pig airways. By direct measures of histamine, cysteinyl-leukotriene and thromboxane release and with studies of allergen-evoked contractions of airway smooth muscle, we describe a complex interplay amongst these autacoids. Notably, we observed an autocrine effect of the cysteinyl-leukotrienes acting through cysLT1 receptors on mast cell leukotriene release. We confirmed the results of previous studies demonstrating a marked enhancement of mast cell mediator release following cyclooxygenase inhibition, but we have extended these results by showing that COX-2 derived eicosanoids inhibit cysteinyl-leukotriene release and yet are without effect on histamine release. Given the prominent role of COX-1 inhibition in aspirin-sensitive asthma, these data implicate preformed mediators stored in granules as the initial drivers of these adverse reactions. Finally, we describe the paracrine signaling cascade leading to thromboxane synthesis in the guinea pig airways following allergen challenge, which occurs indirectly, secondary to cysLT1 receptor activation on structural cells and/ or leukocytes within the airway wall, and a COX-2 dependent synthesis of the eicosanoid. The results highlight the importance of cell-cell and autocrine interactions in regulating allergic responses in the airways.

Effect of Solanum nigrum Linn on Acute and Sub-Acute Models of Inflammation

Objective: The aim of the study was to see the effect of ethanolic extract of Solanum nigrum Linn on Acute and Sub-acute inflammation. Method: Wistar rats weighing 150-200gms were used, divided into four groups Group 1 was control group, two groups Group 2 and 3 treated with the plant extracts at 100 & 200 mg/kg b.w and Group 4 treated with indomethacin, 10 mg/kg b.w. Acute inflammation was induced by injecting 0.1 mL of 1% homogenized carrageenan suspension in normal saline to the right hind paw of the rats prior to which drug treatment was given and paw volume was measured using a digital plethysmometer. Sub-acute anti-inflammatory studies were carried out as described by winter and Porter and hematological parameters were estimated. The granuloma tissue formed during the proliferative process was isolated and wet and dry exudates formation was estimated in various treatment groups. The effect of extract and indomethacin on vital organs like liver, kidney, stomach was also studied by performing histological studies. Results: Study shows that the hydroalcoholic extract of whole plant of Solanum nigrum L. is effective only at higher dose effectively suppressing carrageenan induced inflammation suggesting the inhibition of release of prostaglandin, bradykinin, leukotrienes and polymorphonuclear cells. The histological studies further confirm the anti-inflammatory property of the extract while simultaneously maintaining normal cellular architecture of vital organs than as compared to indomethacin treated group. Conclusion: The ethanolic extract of whole plant of Solanum nigrum Linn shows promising anti-inflammatory activity on both acute and sub-acute stages of inflammation. Key words: Acute Inflammation, Sub-acute Inflammation, Anti-inflammatory activity, Solanum nigrum , Hematological parameters, Histological studies.

In Vivo Cysteinyl Leukotriene Release in Allergic and Nonallergic Immediate Hypersensitivity Reactions during Anesthesia.

Immediate hypersensitivity reactions occurring during anesthesia are classified as allergic when skin tests and mast cell tryptase are positive and as nonallergic when negative results are obtained. Cysteinyl leukotrienes (cysLTs) are potent mediators synthesized by mast cell and eosinophil that induce bronchial constriction. They could play a role in hypersensitivity reactions. cysLT C4, D4, and E4 concentrations were measured by a competition immunoassay in serial plasma samples obtained prospectively from 21 anesthetized controls and retrospectively from 34 patients who reacted at induction of anesthesia (24 with allergic and 10 with nonallergic reactions). In controls, the median (interquartile range) cysLT concentration was 0.83 (0.69 to 1.02) μg/l before anesthesia and was unchanged 30 min, 6 h, and 24 h afterward. In the patients with allergic reactions, the values were highly increased 30 to 60 min after the reaction (17.9 [7.8 to 36.0] μg/l), while the patients with nonallergic reactions had less increased values (7.3 [3.0 to 11.5] μg/l). The difference between the three groups was significant (P < 0.0001). Increased values persisted during the 24 h of observation. Concentrations were significantly higher in patients with bronchospasm (P = 0.016). cysLTs appear to be an important mediator of allergic and nonallergic immediate hypersensitivity reactions. These findings might open a new field for management of patients with hypersensitivity reactions, especially nonallergic ones.

English

Wissadula periplocifolia (L.) C. Presl. is a medicinal plant widely distributed in USA, but it has not yet been investigated extensively. Some pharmacochemical studies were performed at the Federal University of Paraiba, and the components of the crude ethanolic extract were identified; one of them was a tiliroside, which has already been shown to have excellent anti-inflammatory activity that can inhibit the arachidonic acid cascade and can inhibit the release of prostaglandins, prostacyclins, and leukotrienes from leukocytes and neutrophils. This study aimed to verify the possible long-term toxicity of this plant. Chronic toxicity tests were performed, including all recommended parameters; Wistar rats of both sexes were treated with 3 doses of the ethanolic extract of W. periplocifolia (L.) C. Presl leaves, and 2 satellite groups and a control group were set. The platelet and white blood cell counts for all treated males were higher than those in the controls. The anatomopathological tests did not reveal any alterations which were consistent with those obtained from the biochemical tests. Key words: Chronic toxicity test, medicinal plants, phytotherapeutic, Wissadula periplocifolia (L) C. Presl.

Age dictates a steroid-resistant cascade of Wnt5a, transglutaminase 2, and leukotrienes in inflamed airways

Airway remodeling is a detrimental and refractory process showing age-dependent clinical manifestations that are mechanistically undefined. The leukotriene (LT) and wingless/integrase (Wnt) pathways have been implicated in remodeling, but age-specific expression profiles and common regulators remained elusive. We sought to study the activation of the LT and Wnt pathways during early- or late-onsetallergic airway inflammation and to address regulatory mechanisms and clinical relevance in normal human bronchial epithelial cells (NHBEs) and nasal polyp tissues. Mice were sensitized with house dust mite (HDM) allergens from days 3, 15, or 60 after birth. Remodeling factors in murine bronchoalveolar lavage fluid, lung tissue, or human nasal polyp tissue were analyzed by means of Western blotting, immunoassays, or histology. Regulatory mechanisms were studied in cytokine/HDM-stimulated NHBEs and macrophages. Bronchoalveolar lavage fluid LT levels were increased in neonatal and adult but reduced in juvenile HDM-sensitized mice. Lungs of neonatally sensitized mice showed increased 5-lipoxygenase levels, whereas adult mice expressed more group 10 secretory phospholipase A2, Wnt5a, and transglutaminase 2 (Tgm2). Older mice showed colocalization of Wnt5a and LT enzymes in the epithelium, a pattern also observed in human nasal polyps. IL-4 promoted epithelial Wnt5a secretion, which upregulated macrophage Tgm2 expression, and Tgm2 inhibition in turn reduced LT release. Tgm2, group 10 secretory phospholipase A2, and LT enzymes in NHBEs and nasal polyps were refractory to corticosteroids. Our findings reveal age differences in LT and Wnt pathways during airway inflammation and identify a steroid-resistant cascade of Wnt5a, Tgm2, and LTs, which might represent a therapeutic target for airway inflammation and remodeling.

380 Age dictates a steroid resistant cascade of wnt5a, transglutaminase-2 and leukotrienes in inflamed airways

Airway remodeling is a detrimental and refractory process showing age-dependent clinical manifestations that are mechanistically undefined. The leukotriene (LT) and wingless/integrase (Wnt) pathways have been implicated in remodeling, but age-specific expression profiles and common regulators remained elusive.We sought to study the activation of the LT and Wnt pathways during early- or late-onset allergic airway inflammation and to address regulatory mechanisms and clinical relevance in normal human bronchial epithelial cells (NHBEs) and nasal polyp tissues.Mice were sensitized with house dust mite (HDM) allergens from days 3, 15, or 60 after birth. Remodeling factors in murine bronchoalveolar lavage fluid, lung tissue, or human nasal polyp tissue were analyzed by means of Western blotting, immunoassays, or histology. Regulatory mechanisms were studied in cytokine/HDM-stimulated NHBEs and macrophages.Bronchoalveolar lavage fluid LT levels were increased in neonatal and adult but reduced in juvenile HDM-sensitized mice. Lungs of neonatally sensitized mice showed increased 5-lipoxygenase levels, whereas adult mice expressed more group 10 secretory phospholipase A2, Wnt5a, and transglutaminase 2 (Tgm2). Older mice showed colocalization of Wnt5a and LT enzymes in the epithelium, a pattern also observed in human nasal polyps. IL-4 promoted epithelial Wnt5a secretion, which upregulated macrophage Tgm2 expression, and Tgm2 inhibition in turn reduced LT release. Tgm2, group 10 secretory phospholipase A2, and LT enzymes in NHBEs and nasal polyps were refractory to corticosteroids.Our findings reveal age differences in LT and Wnt pathways during airway inflammation and identify a steroid-resistant cascade of Wnt5a, Tgm2, and LTs, which might represent a therapeutic target for airway inflammation and remodeling.

Asthma and Rhinitis Induced by Selective Immediate Reactions to Paracetamol and Non-steroidal Anti-inflammatory Drugs in Aspirin Tolerant Subjects.

In subjects with non-steroidal anti-inflammatory drugs (NSAIDs)- exacerbated respiratory disease (NERD) symptoms are triggered by acetyl salicylic acid (ASA) and other strong COX-1 inhibitors, and in some cases by weak COX-1 or by selective COX-2 inhibitors. The mechanism involved is related to prostaglandin pathway inhibition and leukotriene release. Subjects who react to a single NSAID and tolerate others are considered selective responders, and often present urticaria and/or angioedema and anaphylaxis (SNIUAA). An immunological mechanism is implicated in these reactions. However, anecdotal evidence suggests that selective responders who present respiratory airway symptoms may also exist. Our objective was to determine if subjects might develop selective responses to NSAIDs/paracetamol that manifest as upper/lower airways respiratory symptoms. For this purpose, we studied patients reporting asthma and/or rhinitis induced by paracetamol or a single NSAID that tolerated ASA. An allergological evaluation plus controlled challenge with ASA was carried out. If ASA tolerance was found, we proceeded with an oral challenge with the culprit drug. The appearance of symptoms was monitored by a clinical questionnaire and by measuring FEV1 and/or nasal airways volume changes pre and post challenge. From a total of 21 initial cases, we confirmed the appearance of nasal and/or bronchial manifestations in ten, characterized by a significant decrease in FEV1% and/or a decrease in nasal volume cavity after drug administration. All cases tolerated ASA. This shows that ASA tolerant subjects with asthma and/or rhinitis induced by paracetamol or a single NSAID without skin/systemic manifestations exist. Whether these patients represent a new clinical phenotype to be included within the current classification of hypersensitivity reactions to NSAIDs requires further investigation.

Purification, characterization and allergenicity assessment of 26kDa protein, a major allergen from Cicer arietinum.

Chickpea (CP), a legume of the family Fabaceae, is an important nutrient-rich food providing protein, essential amino acids, vitamins, dietary fibre, and minerals. Unfortunately, several IgE-binding proteins in CP have been detected that are responsible for allergic manifestations in sensitized population. Therefore, the prevalence of CP induced allergy prompted us towards purification, characterization and allergenicity assessment of a major ∼26kDa protein from chickpea crude protein extract (CP-CPE). Purification of CP 26kDa protein was done using a combination of fractionation and anion exchange chromatography. This protein was further characterized as "Chain A, crystal structure of a plant albumin" from Cicer arietinum with Mol wt 25.8kDa by Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Further, allergenic potential of purified 25.8kDa protein was assessed using in vivo and in vitro model. Purified protein showed IgE-binding capacity with sensitized BALB/c mice and CP allergic patient's sera. Enhanced levels of specific and total IgE, MCP-1, MCPT-1, myeloperoxidase, histamine, prostaglandin D2, and cysteinyl leukotriene were found in sera of mice treated with CP ∼26kDa protein. Further, expressions of Th2 cytokines (i.e. IL-4, IL-5, IL-13), transcription factors (i.e. GATA-3, STAT-6, SOCS-3) and mast cell signaling proteins (Lyn, cFgr, Syk, PLC-γ2, PI-3K, PKC) were also found increased at mRNA and protein levels in the intestines of mice treated with CP ∼26kDa protein. In addition, enhanced release of β-hexosaminidase, histamine, cysteinyl leukotriene and prostaglandin D2 were observed in RBL2H3 cell line when treated (125μg) with CP 26kDa protein. Conclusively, in vivo and in vitro studies revealed the allergenic potential of purified CP 26kDa protein. Being a potential allergen, plant albumin may play a pivotal role in CP induced allergenicity. Current study will be helpful for better development of therapeutic approaches to prevent the allergenicity in CP sensitized individuals.

Frankincense--therapeutic properties.

Recently, increasing interest in natural dietary and therapeutic preparations used as dietary supplements has been observed. One of them is frankincense. This traditional medicine of the East is believed to have anti-inflammatory, expectorant, antiseptic, and even anxiolytic and anti-neurotic effects. The present study aims to verify the reported therapeutic properties of Boswellia resin and describe its chemical composition based on available scientific studies. The main component of frankincense is oil (60%). It contains mono- (13%) and diterpenes (40%) as well as ethyl acetate (21.4%), octyl acetate (13.4%) and methylanisole (7.6%). The highest biological activity among terpenes is characteristic of 11-keto-ß-acetyl-beta-boswellic acid, acetyl-11-keto-ß-boswellic acid and acetyl-α-boswellic acid. Contemporary studies have shown that resin indeed has an analgesic, tranquilising and anti-bacterial effects. From the point of view of therapeutic properties, extracts from Boswellia serrata and Boswellia carterii are reported to be particularly useful. They reduce inflammatory conditions in the course of rheumatism by inhibiting leukocyte elastase and degrading glycosaminoglycans. Boswellia preparations inhibit 5-lipoxygenase and prevent the release of leukotrienes, thus having an anti-inflammatory effect in ulcerative colitis, irritable bowel syndrome, bronchitis and sinusitis. Inhalation and consumption of Boswellia olibanum reduces the risk of asthma. In addition, boswellic acids have an antiproliferative effect on tumours. They inhibit proliferation of tumour cells of the leukaemia and glioblastoma subset. They have an anti-tumour effect since they inhibit topoisomerase I and II-alpha and stimulate programmed cell death (apoptosis).

Prostaglandin E2 inhibits mast cell–dependent bronchoconstriction in human small airways through the E prostanoid subtype 2 receptor

Inhaled prostaglandin (PG) E2 might inhibit asthmatic responses, but the mechanisms involved remain undefined. We sought to characterize the direct and indirect effects of PGE2 on human small airways with particular reference to the receptors mediating the responses. Contraction and relaxation were studied in isolated human bronchi with an inner diameter of 1 mm or less. Low concentrations of PGE2 (0.01-1 μmol/L) relaxed the bronchi precontracted by histamine. The bronchodilator response was inhibited by the E prostanoid (EP) subtype 4 receptor antagonist ONO-AE3-208 but unaffected by the EP2 receptor antagonist PF-04418948. Higher concentrations of PGE2 (10-100 μmol/L) contracted the small airways. However, the TP receptor agonists U-46,619, PGF2α, and PGD2 were more potent than PGE2. Moreover, the bronchoconstrictor responses to PGE2 and all other tested prostanoids, including the EP1/EP3 receptor agonist 17-phenyl trinor PGE2 and the partial FP receptor agonist AL-8810, were uniformly abolished by the TP receptor antagonist SQ-29,548. In the presence of TP and EP4 antagonists, PGE2 inhibited the mast cell-mediated bronchoconstriction resulting from anti-IgE challenge. Measurement of the release of histamine and cysteinyl leukotrienes documented that this bronchoprotective action of PGE2 was mediated by the EP2 receptor, unrelated to bronchodilation, and increased with time of exposure. The pharmacology of PGE2 in isolated human small airways was different from its profile in animal models. This first demonstration of powerful EP2 receptor-mediated inhibition of IgE-dependent contractions in human airways introduces a new selective target for the treatment of asthma. This EP2 control of mast cell-mediated bronchoconstriction is presumably exaggerated in patients with aspirin-exacerbated respiratory disease.

House dust mites induce asthmatic smooth muscle cell proliferation through epithelium- and leukotrienes-dependent pathways

Introduction Asthma is a very frequent airway disease that affects 5 to 20% of the whole population worldwide. Whereas the mortality of asthma has been dramatically decreased within the last 10 years, uncontrolled asthma still induces major consequences on morbidity, quality of life, and economic burden. Asthma control determinants have been associated to indoor allergens sensitization. The most frequent indoor allergen is the house dust mites (HDM), which act in vivo on bronchial epithelial layer. Uncontrolled asthma has also been associated with bronchial remodeling and more specifically to the increased mass of bronchial smooth muscle (BSM). It is now well admitted that, BSM remodeling is related with an increase of asthmatic BSM cell proliferation both in vitro and in vivo. However, the relationship between HDM stimulation of the bronchial epithelial layer and BSM remodeling is unknown. Methods We have developed an in vitro culture model of epithelium in air liquid interface (ALI) and BSM interaction. We assessed BSM proliferation using BrdU incorporation. We explored the role of leukotrienes in such a proliferation. We assessed the expression of enzymes involved in the leukotrienes synthesis pathway using RT-PCR. Leukotrienes release was assessed by Elisa in vitro on epithelial cell supernatant and in vivo in mouse broncho-alveolar lavage fluid. Finally, leukotrienes receptor expression was assessed both in vitro by flow cytometry and ex vivo by laser microdissection and RT-PCR. Results We found that epithelial stimulation by HDM increased the proliferation of asthmatic BSM cells and not that of non-asthmatics. The mechanisms involved an epithelial production of leukotrienes C4 and an over-expression of leukotrienes receptor CysLTR1 by asthmatic BSM cells both in vitro and in vivo. Conclusions This work demonstrates the role of HDM on BSM remodeling that occurs only in asthmatic patients and highlights different therapeutic targets at both epithelial and smooth muscle levels.

Genetic Variants in Arachidonic Acid Pathway Genes Associated with Nsaids-Exacerbated Respiratory Disease

Non steroidal anti-inflammatory drugs (NSAIDs) are the most frequent cause of hypersensitivity drug reactions (HDR). The mechanism of NSAIDs-exacerbated respiratory disease (NERD) has been attributed to the inhibition of prostaglandin-endoperoxide synthases (PTGS) by NSAIDs in susceptible individuals. This leads to a reduction in prostaglandin E2production and shunts arachidonic acid metabolism toward the lipooxygenase pathway, resulting in the release of cysteinyl leukotrienes. Here, we have examined the association between NERD and polymorphisms in genes encoding PTGS, lipoxygenases and their receptors.

Human-derived cathelicidin LL-37 directly activates mast cells to proinflammatory mediator synthesis and migratory response

Cathelicidins, a family of antimicrobial peptides, are well known for their role in host defense, particularly against bacteria. Apart from direct killing of microbes through the membrane disruption, cathelicidins can also exert immunomodulatory effects on cells involved in inflammatory processes. Considering the important role of mast cells in inflammation, the aim of this study was to determine whether LL-37, human-derived cathelicidin, can induce mast cell activation. We have observed that LL-37 directly stimulates mast cell to degranulation and production of some proinflammatory cytokines, but fails to induce cysteinyl leukotriene generation and release. We have also documented that LL-37 acts as a strong mast cell chemoattractant. In intracellular signaling in mast cells activated by LL-37 participates PLC/A2 and, in part, MAPKs, and PI3K. In conclusion, our results indicate that cathelicidins may enhance antibacterial inflammatory response via attracting mast cell to pathogen entry site and via induction of mast cell-derived mediator release.

Interchangeability and comparative effectiveness between generic and brand montelukast immediate release tablets after a single oral administration in healthy volunteers

BackgroundMontelukast is a leukotriene receptor antagonist. The release of leukotrienes causes narrowing and constricting in the respiratory airways. Blocking the action of these leukotrienes, montelukast can be used for the prophylaxis and treatment of chronic asthma.ObjectiveThe aim of this study was to evaluate the interchangeability and comparative effectiveness between a generic and a brand montelukast 10 mg immediate release tablets (Broncast® and Singulair®, respectively) after a single oral dose among Arab Mediterranean volunteers.MethodsAn open-label, randomized two-period crossover bioequivalence design was conducted in 31 healthy male volunteers with a 1 week washout between each study period and under fasting conditions. The plasma drug concentration was assessed by using a previously validated LC MS/MS method. The ratio between the generic and brand of geometric least squares means was reported for both generic and brand products. Moreover, an in vitro dissolution study was conducted on generic and brand tablets using three different pH media, and similarity and non-similarity factors (f2 and f1) were calculated.ResultsThe used bioanalytical method was found to be linear within the range 6.098–365.855 ng/mL. The correlation coefficient was close to 0.999 during the course of the study validation. Statistical comparison of the main pharmacokinetic parameters showed the inexistence of any significant difference between generic and the brand. The point estimates (ratios of geometric means) were 111.939, 111.711, and 112.169 % for AUC0–24, AUC0–∞, and Cmax, respectively. The 90 % confidence intervals (CIs) were within the pre-defined limits of 80.00–125.00 % as specified by the FDA and EMA for bioequivalence studies. F2 and f1 were higher than 50 and lower than 15, respectively in all selected pH media.ConclusionBroncast® immediate release film coated tablets (10 mg/tablet) are bioequivalent to Singulair® immediate release film coated tablets (10 mg/tablet), with a comparable safety and efficacy profile. This suggests that these two formulations can be clinically considered interchangeable. The dissolution study suggests that it could be used as premarketing quality control parameter in order to maintain the high quality of the produced product.

Simultaneous quantification of leukotrienes and hydroxyeicosatetraenoic acids in cell culture medium using liquid chromatography/tandem mass spectrometry.

Leukotrienes (LTs) and hydroxyeicosatetraenoic acids (HETEs) are important bioactive lipid mediators that participate in various pathophysiological processes. To advance understanding of the mechanisms that regulate these mediators in physiological and pathological processes, an analytical method using liquid chromatography/tandem mass spectrometry for the simultaneous quantification of LTB4, LTC4, LTD4, LTE4, 5-HETE, 8-HETE, 12-HETE and 15-HETE in cell culture media was developed. A Supel™-Select HLB solid-phase extraction cartridge was used for sample preparation. The compounds were separated on a C18 column using gradient elution with acetonitrile-water-formic acid (20:80:0.1, v/v/v) and acetonitrile-formic acid (100:0.1, v/v). The calibration curves of LTB4, LTD4, LTE4 and HETEs were linear in the range of 0.025-10 ng/mL, and the calibration curve of LTC4 was linear in the range of 0.25-10 ng/mL. Validation assessment showed that the method was highly reliable with good accuracy and precision. The stability of LTs and HETEs was also investigated. Using the developed method, we measured LTs and HETEs in the culture supernatant of the human mast cell line HMC-1. The present method could facilitate investigations of the mechanisms that regulate the production, release and signaling of LTs and HETEs.

20(S)-Protopanaxatriol inhibits release of inflammatory mediators in immunoglobulin E-mediated mast cell activation

BackgroundAntiallergic effect of 20(S)-protopanaxatriol (PPT), an intestinal metabolite of ginseng saponins, was investigated in guinea pig lung mast cells and mouse bone marrow-derived mast cells activated by a specific antigen/antibody reaction. MethodsIncreasing concentrations of PPT were pretreated 5min prior to antigen stimulation, and various inflammatory mediator releases and their relevant cellular signaling events were measured in those cells. ResultsPPT dose-dependently reduced the release of histamine and leukotrienes in both types of mast cells. Especially, in activated bone marrow-derived mast cells, PPT inhibited the expression of Syk protein, cytokine mRNA, cyclooxygenase-1/2, and phospholipase A2 (PLA2), as well as the activities of various protein kinase C isoforms, mitogen-activated protein kinases, PLA2, and transcription factors (nuclear factor-κB and activator protein-1). ConclusionPPT reduces the release of inflammatory mediators via inhibiting multiple cellular signaling pathways comprising the Ca2+ influx, protein kinase C, and PLA2, which are propagated by Syk activation upon allergic stimulation of mast cells.

Allergic manifestation by black gram (Vigna mungo) proteins in allergic patients, BALB/c mice and RBL-2H3 cells.

The prevalence of black gram (Vigna mungo) induced allergic reactions are reported from several parts of the world including Asia and Australia. But, a thorough exploration of the allergic reactions induced by black gram proteins is still lacking. Therefore, efforts have been made to explore black gram allergy using in vivo and in vitro approaches. In this study, Simulated Gastric Fluid (SGF) assay and IgE immunoblotting were carried out to identify clinically relevant allergens of black gram. BALB/c mice and RBL-2H3 cells were used for elucidation of allergenic reactions of black gram proteins. Further, this study was extended to screen black gram sensitive patients among nasobronchial allergic patients on the basis of clinical history, skin prick test (SPT), specific IgE levels and IgE immunoblotting. Enhanced levels of specific IgE, IgG1/IgG2a (p < 0.05), histamine (p < 0.05), clinical symptoms, pathological indications in the lungs, intestine and spleen were evident in black gram sensitized BALB/c mice. Moreover, the expression of Th2 cytokine transcripts and GATA-3/T-bet ratio was found enhanced in the treated group. In vitro studies on RBL-2H3 cells,showed increased release of β-hexosaminidase (p < 0.05), histamine (p < 0.05), cysteinyl leukotriene (p<0.05) and prostaglandin D2 (p < 0.05). Further, 8.5% of screened patients were found allergic to black gram and concomitant sensitization with other allergens has shown the possibility of further enhancement in allergenic problem. Conclusively, the present study suggested that black gram consumption may be responsible for inducing immediate type of allergic sensitization in susceptible subjects.