Nebulized Mannitol, Particle Distribution, and Cough in Idiopathic Pulmonary Fibrosis.

BACKGROUND: Inhaled interferon, a potential treatment for idiopathic pulmonary fibrosis, must be formulated with mannitol, which can cause bronchospasm and cough. Coughing during drug inhalation can be affected by many factors, but some factors are fixed by the needs of the formulation and inflammatory disease in the airways. A component of the cough response may be related to sites of deposition, particularly upper and central airways. If deposition sites are important, then manipulating the particle distribution of the aerosol may mitigate coughing. To design a therapeutic formulation and delivery system for formulations that contain mannitol, we tested the effect of particle distribution on cough during mannitol inhalation in volunteers with idiopathic pulmonary fibrosis. METHODS: A solution of mannitol was formulated to match requirements for future interferon formulations (40 mg/mL, 220 mOsm/L). Mannitol aerosols were generated by using different nebulizers providing particle distributions that were expected to vary upper airway deposition. The nebulizer fill volume was adjusted to correct for differences in nebulizer efficiency with a target inhaled mass of 20 mg. Particle distributions were measured by cascade impaction (mass median aerodynamic diameters, 1.2 and 6.5 µm). Seven subjects with idiopathic pulmonary fibrosis participated in the study. To maximize deposition, the subjects were trained to inhale slowly and deeply (6 s inspiration). Spirometry was measured before and after inhalation. The study was carried out on separate days (day 1: 1.2 µm; day 2: 6.5 µm), and the pattern of coughing was observed. RESULTS: Coughing was often spontaneous and provoked by spirometry. When inhaling the 1.2-µm distribution, no subject coughed during inhalation. Six of the seven subjects coughed when inhaling the 6.5-µm particles. Spirometry was unaffected. CONCLUSIONS: In subjects with idiopathic pulmonary fibrosis, nebulized mannitol can cause coughing. Modifying the aerosol distribution prevents coughing during mannitol inhalation. Mannitol aerosols can be inhaled safely without bronchospasm. These data serve to inform future formulation and/or device combinations for planned interferon therapy.

A comparison of myocardial perfusion and rejection in cardiac transplant patients.

INTRODUCTION: Although histological evaluation of the cardiac tissue is the current gold standard for evaluation of rejection, we hypothesized that cardiac perfusion MRI is a safe non-invasive method that correlates tissue blood flow changes with biopsy proven rejection in the cardiac transplant patient. MATERIALS AND METHODS: In a retrospective study from 1984-2001, 83 patients underwent 135 MR Gd-DTPA imaging studies. In 8 patients (9%), biopsies graded 2 or higher (by ISHLT criteria) provided evidence of rejection. Patients were age and sex matched to 11 non-rejected controls for imaging analysis. Time-signal intensity curves generated for a mid-ventricle LV short axis slice during rest and adenosine stress allowed determination of myocardial blood flow (MBF, ml/min/gm). ROC curve analysis by SPSS allowed estimation of sensitivity and specificity. RESULTS: At rest, there was no difference in MBF between patients with prior rejection vs. those without (1.18 +/- 0.26 vs. 1.16 +/- 0.29). At stress there was a decrease in MBF for patients with prior rejection episodes (3.27 +/- 0.74) compared to no rejection (3.60 +/- 0.72), P = 0.067). The area under the ROC curve was 0.82, with specificity and sensitivity of 75% and 81%, respectively. CONCLUSION: This study suggests that perfusion MR imaging can be used in assessing the cardiac transplant patient for rejection related microvascular changes. The high specificity and sensitivity recorded from the ROC curve illustrates the potential utility of this diagnostic test for future studies.