iloprost and Bronchial-Hyperreactivity

To determine the feasibility of administering iloprost by inhalation in patients with mild atopic asthma.. Volunteers underwent supervised inhalation of iloprost in the clinic with measurement of spirometry and blood pressure for 2 hours. The volunteers then inhaled iloprost four times daily at a dose of 2.5 or 5 μg for 14 days. Spirometry, asthma questionnaires, peak flow diaries, measurement of methacholine responsiveness, and exhaled nitric oxide concentrations were obtained prior to and after the treatment period.. Chronic inhalation of iloprost (2.5-5 μg) did not alter spirometry or methacholine responsiveness.. Inhaled iloprost in carefully selected volunteers with mild asthma appears to be a suitable intervention to explore the effects of prostacyclin in human asthma.

Topics: Administration, Inhalation; Adult; Asthma; Blood Pressure; Bronchial Hyperreactivity; Dose-Response Relationship, Drug; Female; Humans; Iloprost; Male; Middle Aged; Nitric Oxide; Prostaglandins I; Spirometry

The development of bronchial hyperreactivity (BHR) subsequent to precapillary pulmonary hypertension (PHT) was prevented by acting on the major signalling pathways (endothelin, nitric oxide, vasoactive intestine peptide (VIP) and prostacyclin) involved in the control of the pulmonary vascular and bronchial tones.. Five groups of rats underwent surgery to prepare an aorta-caval shunt (ACS) to induce sustained precapillary PHT for 4 weeks. During this period, no treatment was applied in one group (ACS controls), while the other groups were pretreated with VIP, iloprost, tezosentan via an intraperitoneally implemented osmotic pump, or by orally administered sildenafil. An additional group underwent sham surgery. Four weeks later, the lung responsiveness to increasing doses of an intravenous infusion of methacholine (2, 4, 8 12 and 24 μg/kg/min) was determined by using the forced oscillation technique to assess the airway resistance (Raw).. BHR developed in the untreated rats, as reflected by a significant decrease in ED50, the equivalent dose of methacholine required to cause a 50% increase in Raw. All drugs tested prevented the development of BHR, iloprost being the most effective in reducing both the systolic pulmonary arterial pressure (Ppa; 28%, p = 0.035) and BHR (ED50 = 9.9 ± 1.7 vs. 43 ± 11 μg/kg in ACS control and iloprost-treated rats, respectively, p = 0.008). Significant correlations were found between the levels of Ppa and ED50 (R = -0.59, p = 0.016), indicating that mechanical interdependence is primarily responsible for the development of BHR.. The efficiency of such treatment demonstrates that re-establishment of the balance of constrictor/dilator mediators via various signalling pathways involved in PHT is of potential benefit for the avoidance of the development of BHR.

Topics: Administration, Oral; Airway Resistance; Analysis of Variance; Animals; Antihypertensive Agents; Blood Pressure; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoconstriction; Disease Models, Animal; Endothelin Receptor Antagonists; Endothelins; Hypertension, Pulmonary; Iloprost; Infusion Pumps, Implantable; Infusions, Parenteral; Lung; Lung Volume Measurements; Male; Nitric Oxide; Phosphodiesterase 5 Inhibitors; Piperazines; Prostaglandins I; Purines; Pyridines; Rats; Rats, Sprague-Dawley; Receptors, Endothelin; Signal Transduction; Sildenafil Citrate; Sulfones; Tetrazoles; Time Factors; Vasoactive Intestinal Peptide; Vasodilator Agents