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Updated: May 18, 2026
Murine Model of Allergen Induced Asthma
Published on: May 14, 2012
Matrix metalloproteinase-9 increases in the sputum from allergic occupational asthma patients after specific
Roberto Castano1, David Miedinger, Karim Maghni
1Department of Surgery/Otolaryngology, Axe de recherche en santé respiratoire, Hôpital du Sacré-Coeur de Montréal, Montreal, Que., Canada. roberto.castano@umontreal.ca
Background:
Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) play a role in the pathogenesis of asthma. MMP-9 increases in the sputum of asthmatic patients after bronchial challenge with common allergens. We sought to assess whether a high-molecular-weight occupational allergen was able to induce changes in MMP-9 as well as in other MMPs and TIMPs in subjects with occupational asthma.
Methods:
Ten patients underwent specific inhalation challenge (SIC) on 2 consecutive days. We monitored changes in lung function by measuring FEV(1) for 7 h. Induced sputum test was performed at 6 h after sham and flour challenge. The total and differential cell counts were analyzed. Levels of MMPs (specifically MMP-2, MMP-7, MMP-9 and MMP-13) were measured using Fluorokine® MultiAnalyte Profiling kits and a Luminex® Bioanalyzer, while levels of TIMP-1 and TIMP-2 were measured by ELISA.
Results:
Flour challenge increased the percentage of eosinophils in sputum samples. Asthmatic reactions induced by flour were associated with a significant increase in the sputum level of MMP-9 (p = 0.05), but not in the levels of MMP-2, MMP-7, MMP-13, TIMP-1 and TIMP-2. Sputum levels of MMP-9 measured after flour challenge were nearly significantly correlated (r = 0.67; p = 0.06) with the maximal fall in FEV(1) observed during the asthmatic reaction, but they did not correlate with the number of neutrophils (r = 0.18; p = 0.7) and eosinophils (r = 0.55; p = 0.2).
Conclusions:
This study showed that MMP-9 increases in sputum samples from sensitized occupational asthma patients after SIC with flour.
Insights
Occupational asthma triggered by flour inhalation increases sputum matrix metalloproteinase-9 (MMP-9) levels. This specific enzyme elevation is linked to lung function decline in sensitized patients.
Area of Science:
- Immunology
- Respiratory Medicine
- Occupational Health
Background:
- Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are implicated in asthma pathogenesis.
- Elevated MMP-9 is observed in asthmatic patients' sputum post-allergen challenge.
- The role of high-molecular-weight occupational allergens in MMP/TIMP modulation requires further investigation.
Purpose of the Study:
- To investigate the impact of a high-molecular-weight occupational allergen (flour) on MMP-9 and other MMPs/TIMPs in occupational asthma.
- To assess changes in lung function and sputum biomarkers following specific inhalation challenge (SIC).
Main Methods:
- Ten patients with occupational asthma underwent a 2-day specific inhalation challenge (SIC) with flour.
- Lung function (FEV1) was monitored for 7 hours post-challenge.
- Induced sputum was analyzed for cell counts and levels of MMP-2, MMP-7, MMP-9, MMP-13, TIMP-1, and TIMP-2.
Main Results:
- Flour challenge significantly increased eosinophils in sputum.
- Sputum MMP-9 levels significantly increased post-flour challenge (p = 0.05).
- MMP-9 levels showed a near-significant correlation with maximal FEV1 fall during asthmatic reactions (r = 0.67; p = 0.06).
Conclusions:
- Specific inhalation challenge with flour increases MMP-9 in the sputum of sensitized occupational asthma patients.
- MMP-9 elevation is a potential biomarker associated with flour-induced occupational asthma severity.
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