Low sputum MMP-9/TIMP ratio is associated with airway narrowing in smokers with asthma
Bibliographic record
Abstract
Asthmatic smokers have poor symptom control and accelerated decline in lung function. A reduced ratio of matrix metalloproteinase (MMP)-9/tissue inhibitors of metalloproteinases (TIMPs) in nonsmokers with asthma has been implicated in airway remodelling. We tested the hypothesis that sputum MMP-9 activity/TIMPs ratios are reduced in smokers compared with never-smokers with asthma and are associated with reduced lung function and altered computed tomography (CT) measures of airway wall dimensions. Lung function, airway dimensions by CT, and induced sputum concentrations (and activity) of MMP-9 and TIMP-1 and -2 were measured in 81 asthmatics and 43 healthy subjects (smokers and never-smokers). Respiratory epithelial MMP9 and TIMP mRNA was quantified in 31 severe asthmatics and 32 healthy controls. Sputum MMP-9 activity/TIMP-1 and TIMP-2 ratios, and nasal epithelial MMP9/TIMP1 and MMP9/TIMP2 expression ratios were reduced in smokers with asthma compared with never-smokers with asthma. Low sputum ratios in asthmatic smokers were associated with reduced post-bronchodilator forced expiratory volume in 1 s (FEV1), FEV1/forced vital capacity ratio and segmental airway lumen area. The association of a low sputum MMP-9 activity/TIMP-1 ratio with persistent airflow obstruction and reduced CT airway lumen area in smokers with asthma may indicate that an imbalance of MMP-9 and TIMPs contributes to structural changes to the airways in this group.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".