sulprostone and Asthma

Prostaglandin (PG) E(2) is thought to exert protective effects in the lungs. Accordingly, aerosolized PGE(2) prevents the experimentally induced airway response to allergen challenge in asthmatics. In vitro evidence indicating that functional PGE(2) receptors (EP) are expressed on human mast cells and that PGE(2) can alter cytokine production suggests that these phenomena may be involved in its beneficial effect in asthma. However, in vivo evidence is scarce.. We assessed the effects of exogenous PGE(2) and of the EP1/EP3 agonist sulprostone on the murine airway response to house dust mite (HDM) allergens, a model that accurately reproduces the spontaneous exposure of allergic asthma patients to aeroallergens. We also analyzed the in vivo impact of PGE(2) on production in the murine airway of mast cell protease (mMCP)-1, a specific marker of lung mast cell activity, and on local production of cytokines.. Exogenous PGE(2), but not sulprostone, reduced eosinophilic infiltration in HDM-sensitized mice by half and led to a strong reduction in airway Th(2) cytokine expression. These anti- inflammatory effects were accompanied in vivo by a substantial reduction in HDM-induced upregulation of airway mMCP-1. Neither PGE(2) nor sulprostone had any effect on airway hyperresponsiveness to methacholine.. Our results indicate that the anti-inflammatory effect of PGE(2) can be reproduced in vivo in HDM-sensitized mice and suggest that this protective effect is dependent in vivo on inhibition of the allergen-triggered proinflammatory activity of bronchial mast cells. Finally, the effect of PGE(2) is linked to reduced upregulation of airway Th(2) cytokines.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Asthma; Chemokine CCL2; Cytokines; Dinoprostone; Disease Models, Animal; Eosinophils; Female; Infusions, Subcutaneous; Lung; Mast Cells; Methacholine Chloride; Mice; Mice, Inbred BALB C; Pulmonary Eosinophilia; Pyroglyphidae; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP1 Subtype; Receptors, Prostaglandin E, EP3 Subtype; Th2 Cells

The mechanism of aspirin (acetylsalicylic acid: ASA) hypersensitivity in asthmatic patients is related to arachidonic acid metabolism abnormalities, and specific triggering by ASA of 15-hydroxyeicosatetraenoic acid (15-HETE) generation was observed in leucocytes from aspirin-sensitive (AS) but not from aspirin-tolerant (AT) asthmatics.. The aim of this study was to identify the enzymatic pathway involved in ASA-induced 15-HETE generation in AS asthmatics and to assess the regulatory role of prostaglandin EP receptors.. Peripheral blood leucocytes (PBLs) were isolated from AS (n=18) and AT (n=20) asthmatics and challenged with ASA, with and without pre-incubation with caffeic acid (CA) [15-lipoxygenase (15-LO) inhibitor] or prostaglandin receptor non-specific (misoprostol, sulprostone) and specific EP1-4 receptors agonists. Eicosanoids were measured in supernatants using specific immunoassays.. Aspirin triggered 15-HETE generation in PBLs of AS asthmatics (mean increase 292%) but not in AT asthmatics and inhibited prostaglandin(2) (PGE(2)) generation in both groups of patients to the same degree. Leucocytes from AS patients produced less PGE(2), both before and after ASA incubation. Pre-incubation of PBLs with CA decreased basal 15-HETE production in all patients and completely inhibited ASA-induced 15-HETE generation in AS asthmatics. CA did not change basal PGE(2) production but enhanced induced by ASA inhibition of PGE(2). Non-specific agonists of EP receptors (misoprostol and sulprostone) did not affect basal 15-HETE production but inhibited in a dose-dependent manner the ASA-induced increase of 15-HETE generation in AS asthmatics. On the contrary, in AT asthmatics, pre-incubation of PBLs with misoprostol or sulprostone resulted in a significant increase in 15-HETE generation after addition of ASA (200 microm). EP1-3 receptor agonists inhibited (range 72-94%) the ASA-induced 15-HETE production significantly.. Our study demonstrated that ASA-triggered 15-HETE generation involves the activation of 15-LO and is modulated by prostaglandin EP1-3 receptors. The relevance of these observations to the mechanism of in vivo ASA-induced asthmatic attack remains to be established.

Topics: Adolescent; Adult; Aged; Arachidonate 15-Lipoxygenase; Aspirin; Asthma; Caffeic Acids; Dinoprostone; Drug Hypersensitivity; Female; Humans; Hydroxyeicosatetraenoic Acids; Leukocytes; Lipoxygenase Inhibitors; Male; Middle Aged; Misoprostol; Receptors, Prostaglandin E