The Pathophysiology of Asthma

Perfluorooctyl bromide (perflubron) stimulates mucin secretion in the ferret trachea

OBJECTIVES

Partial liquid ventilation with perfluorooctyl bromide (perflubron) has been shown to be safe and effective in animal models with respiratory failure. However, airway mucus accumulation has been reported to be a problem in human trials. We hypothesized that this might be because perflubron directly affects mucociliary clearance or stimulates mucus secretion.

METHODS AND RESULTS

We first measured the mucociliary transportability of secretions on the mucus-depleted frog palate exposed to perflubron and demonstrated that the ciliated epithelium remained intact with preservation of mucociliary transport. We then measured mucin and lysozyme secretion from isolated ferret tracheal segments to evaluate the secretagogue potential of perflubron. There was an 86% increase in mucin secretion with perflubron incubation at 40 min (n = 19; p < 0.01) and a 52% increase after 4 h of exposure followed by evaporation of perflubron (n = 19; p < 0.01). There was no significant difference in lysozyme secretion at any time between perflubron-exposed or buffer-exposed tissue (n = 4). The secretagogue effect was completely blocked by nordihydroguaiaretic acid, an inhibitor of arachidonic acid (AA) metabolism.

CONCLUSION

These data suggest that although perflubron does not seem to be harmful to the airway, it induces mucus secretion in a noninflamed airway, and that this can be modulated by inhibitors of AA metabolism.

Asthma and emotion: a review

This review of the empirical literature on the relationship between asthma and emotion presents an explanatory model of the connection between them. Asthmatics tend to report and display a high level of negative emotion, and asthma exacerbations have been linked temporally to periods of heightened emotionality. Causality may be bidirectional. Hypothesized mediators for the relationship between asthma and emotionality include vagal and alpha-sympathetic hyperreactivity, predominant obstruction in the larger airways, individual response stereotypy, direct effects of emotion-related facial muscle tension on the airways, the emotional effects of asthma medications, heightened respiratory drive, and hyperventilation. Predictions are presented for research on this model of asthma and emotion, and for the psychological treatment of asthma.