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Bronchoconstriction induced by inhaled adenosine 5'-monophosphate in subjects with allergic rhinitis
L Prieto1, V Gutiérrez, J Liñana
1Sección de Alergología and Universidad de Valencia, Spain.
Abstract:
Adenosine and its related nucleotide, adenosine 5'-monophosphate (AMP) induce bronchoconstriction in asthmatics, probably caused by histamine release from airway mast cells. The objective of this study was to determine the effect of inhaled AMP on lung function in subjects with allergic rhinitis. A total of 52 adults (28 subjects with allergic rhinitis, 14 asthmatics and 10 healthy subjects) were challenged with increasing concentrations of AMP and methacholine. Airflow was assessed after each concentration and the response to each bronchoconstrictor agent was measured by the provocative concentration required to produce a 20% fall (PC20) in forced expired volume in one second (FEV1). All 14 asthmatics, 10 subjects with allergic rhinitis and none of the healthy controls were hyperresponsive to AMP. Subjects with allergic rhinitis had higher prevalence of hyperresponsiveness to AMP than healthy controls (p=0.038). Although the prevalence of hyperresponsiveness for methacholine and for AMP in subjects with allergic rhinitis was similar (39% and 36%, respectively), four subjects had hyperresponsiveness to methacholine but not to AMP, whereas three subjects had hyperresponsiveness to AMP but not to methacholine. To conclude, inhaled adenosine 5'-monophosphate causes airway narrowing in a significantly higher proportion of subjects with allergic rhinitis than healthy volunteers. Furthermore, methacholine and adenosine 5'-monophosphate hyperresponsiveness are not detected in the same individuals with allergic rhinitis, thus suggesting that responsiveness to the two bronchoconstrictor stimuli is not reflecting the same abnormalities of the airways.
Insights
Inhaled adenosine 5'-monophosphate (AMP) causes airway narrowing in allergic rhinitis patients more than healthy individuals. AMP hyperresponsiveness in allergic rhinitis suggests distinct airway abnormalities compared to methacholine.
Area of Science:
- Respiratory Medicine
- Pulmonology
- Allergy and Immunology
Background:
- Adenosine and adenosine 5 '-monophosphate (AMP) are known to cause bronchoconstriction in asthmatics, potentially via histamine release from mast cells.
- Allergic rhinitis is associated with airway inflammation and hyperresponsiveness, but the role of specific bronchoconstrictors like AMP is less understood.
Purpose of the Study:
- To investigate the effect of inhaled adenosine 5 '-monophosphate (AMP) on lung function in individuals with allergic rhinitis.
- To compare the prevalence of AMP-induced airway hyperresponsiveness in allergic rhinitis patients versus healthy controls and asthmatics.
Main Methods:
- A total of 52 adults (28 with allergic rhinitis, 14 asthmatics, 10 healthy controls) underwent bronchial challenges with increasing concentrations of AMP and methacholine.
- Airflow was measured, and the provocative concentration causing a 20% fall in forced expired volume in one second (PC20) was determined for each agent.
Main Results:
- All asthmatics and 10 subjects with allergic rhinitis were hyperresponsive to AMP, while healthy controls were not.
- The prevalence of AMP hyperresponsiveness was significantly higher in subjects with allergic rhinitis compared to healthy controls (p=0.038).
- While similar proportions of allergic rhinitis subjects showed hyperresponsiveness to methacholine (39%) and AMP (36%), there was discordance, with some individuals responsive to one but not the other.
Conclusions:
- Inhaled adenosine 5 '-monophosphate (AMP) induces airway narrowing in a significantly greater proportion of individuals with allergic rhinitis than in healthy volunteers.
- Hyperresponsiveness to methacholine and AMP in allergic rhinitis patients are not always concurrent, indicating potentially different underlying airway abnormalities.
- These findings suggest that AMP may be a valuable tool for assessing distinct airway pathophysiology in allergic rhinitis.