15-hydroxy-11-alpha-9-alpha-(epoxymethano)prosta-5-13-dienoic-acid and Rhinitis--Allergic--Perennial

Bayer has been interested in the observations that metabolites of arachidonic acid are involved in allergy and inflammation. Ramatroban was thus developed as a therapeutic agent for allergic and inflammatory diseases. Ramatroban showed an antagonistic action on the thromboxane A2 (TXA2) receptor in in vitro experiments using platelets or arteries. It inhibited the permeability of capillary and also the infiltration of eosinophils in nasal mucosa. Ramatroban had an inhibitory effect on the nasal resistance stimulated by either U-46619 or antigen challenge in in vivo experiments. The concentration of nasal TXA2 was increased when the antigen was challenged to allergic patients. Clinical trials demonstrated that ramatroban decreased sneezing, rhinorrhea, and rhinostenosis in patients enrolled in the study. No serious adverse reaction of ramatroban was observed in patients throughout the trials. The treatment with ramatroban is safe and improves nasal symptoms.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Airway Resistance; Animals; Capillary Permeability; Carbazoles; Clinical Trials as Topic; Humans; Nasal Cavity; Nasal Mucosa; Nasal Obstruction; Receptors, Thromboxane; Rhinitis, Allergic, Perennial; Sulfonamides

We examined the role of prostanoid DP receptor in nasal blockage in an experimental allergic rhinitis model in guinea pigs. Local inhalation of prostaglandin D(2) (PGD(2)) to the nasal cavity resulted in an increase in intranasal pressure in guinea pigs actively sensitized by repeated antigen exposure but not in non-sensitized guinea pigs. Nasal hyperresponsiveness was observed when the guinea pigs were exposed to histamine and U-46619 (11alpha, 9alpha-epoxymethano-PGH(2); a thromboxane (TX) A(2) mimetic) after repeated antigen exposure. S-5751 ((Z)-7-[(1R,2R,3S,5S)-2-(5-hydroxybenzo[b]thiophen-3-ylcarbonylamino)-10-norpinan-3-yl]hept-5-enoic acid), a prostanoid DP receptor antagonist, inhibited not only PGD(2)-induced nasal blockage but also nasal hyperresponsiveness to histamine and U-46619 in sensitized guinea pigs. Combined exposure of the nasal cavity of guinea pigs to an aerosol of PGD(2) with histamine or U-46619 at sub-threshold concentrations synergistically caused a marked increase in intranasal pressure. These responses were significantly suppressed by S-5751. These results suggest that PGD(2) plays a critical role in the increase in intranasal pressure via prostanoid DP receptor, probably through synergistically enhancing the nasal response with other chemical mediators released from mast cells and other inflammatory cells activated by allergens.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Administration, Intranasal; Allergens; Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Synergism; Guinea Pigs; Histamine; Male; Nasal Mucosa; Nasal Obstruction; Nose; Ovalbumin; Pressure; Prostaglandin D2; Receptors, Immunologic; Receptors, Prostaglandin; Rhinitis, Allergic, Perennial; Thiophenes; Time Factors

S-1452, a selective thromboxane (Tx) A(2) receptor (TP-receptor) antagonist, was evaluated in antigen- and U-46619 (a TxA(2) mimetic)-induced guinea pig nasal plasma exudation models. Exposure of the nasal cavity of actively sensitized guinea pigs to aerosolized ovalbumin (OA) caused marked exudation of dye into both the nasal mucosa and nasal airway lumen. These responses were significantly inhibited by S-1452 (30 mg/kg, p.o.) as well as an H(1)-antihistamine, diphenhydramine (5 mg/kg, i.v.). In addition, exposure of the nasal cavity of nonsensitized guinea pigs to aerosolized U-46619 or histamine also resulted in nasal plasma exudation, and S-1452 (1 mg/kg, p.o.) almost completely suppressed the U-46619-induced response but did not affect the histamine-induced one, even at a high dose of 30 mg/kg. These results indicate that TxA(2) as well as histamine may play an important role in antigen-induced nasal plasma exudation in guinea pigs, and S-1452 can be expected to be useful for the treatment of allergic rhinitis.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Antigens; Bridged Bicyclo Compounds; Disease Models, Animal; Fatty Acids, Monounsaturated; Guinea Pigs; Male; Nasal Lavage Fluid; Nasal Mucosa; Prostaglandin Antagonists; Receptors, Thromboxane; Rhinitis, Allergic, Perennial; Vasoconstrictor Agents