Targeting the small airways with dry powder adenosine: A challenging concept

Erica van der Wiel, Anne J Lexmond, Maarten van den Berge, Dirkje S Postma, Paul Hagedoorn, Henderik W Frijlink, Martijn P Farenhorst, Anne H de Boer, Nick H T Ten Hacken

OnderzoeksoutputAcademicpeer review

5 Citaten (Scopus)
282 Downloads (Pure)

Samenvatting

Background: Small-particle inhaled corticosteroids (ICS) provide a higher small airway deposition than large-particle ICS. However, we are still not able to identify asthma patients who will profit most from small-particle treatment. Objective: We aimed to identify these patients by selectively challenging the small and large airways. We hypothesized that the airways could be challenged selectively using small- and large-particle adenosine, both inhaled at a high and a low flow rate. Design: In this cross-over study 11 asthma subjects performed four dry powder adenosine tests, with either small (MMAD 2.7 µm) or large (MMAD 6.0 µm) particles, inhaled once with a low flow rate (30 l min(-1)) and once with a high flow rate (60 l min(-1)). Spirometry and impulse oscillometry were performed after every bronchoprovocation step. We assumed that FEV1 reflects the large airways, and FEF25-75%, R5-R20 and X5 reflect the small airways. Results: The four adenosine tests were not significantly different with respect to the threshold values of FEV1 (p = 0.12), FEF25-75% (p = 0.37), R5-R20 (p = 0.60) or X5 (p = 0.46). Both small- and large-particle adenosine induced a response in the small airways in the majority of the tests. Conclusions: In contrast to our hypothesis, all four adenosine tests provoked a response in the small airways and we could not identify different large- or small-airway responders. Interestingly, even the test with large particles and a high flow rate induced a small-airway response, suggesting that selective challenging of the small airways is not necessary. Future studies should investigate the relation between particle deposition and the site of an airway response.

Originele taal-2English
Artikelnummer1369328
TijdschriftEuropean clinical respiratory journal
Volume4
Nummer van het tijdschrift1
DOI's
StatusPublished - 6-sep.-2017

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