Angiotensin-(1-7) improves oxygenation, while reducing cellular infiltrate and fibrosis in experimental Acute Respiratory Distress Syndrome
Bibliographic record
Abstract
BACKGROUND: The renin-angiotensin system (RAS) plays a role in the pathogenesis of ARDS, Angiotensin II (Ang-II) contributing to the pathogenesis of inflammation and fibrogenesis. Angiotensin-(1-7) (Ang-(1-7)) may antagonize the effects of Ang-II. This study was aimed at evaluating the potential for Ang-(1-7) to reduce injury, inflammation and fibrosis in an experimental model of ARDS in the acute and late phases. METHODS: Male Sprague Dawley rats underwent an instillation of 0.1 M hydrochloric acid (HCl, 2.5 ml/kg) into the right bronchus. In an acute ARDS study, acid-injured rats were subjected to high stretch mechanical ventilation (18 ml/kg) for 5 h and randomized to receive an intravenous infusion of either vehicle (saline), Ang-(1-7) at low dose(0.27 μg/kg/h) (ALD), or high dose (60 μg/kg/h) (AHD) starting simultaneously with injury or 2 h afterwards. Arterial blood gas analysis and bronchoalveolar lavage (BAL) were performed to assess the injury. For the late ARDS study, after HCl instillation rats were randomized to either vehicle or high dose Ang-(1-7) (300 μg/kg/day) infused by mini osmotic pumps for two weeks, and lung hydroxyproline content measured. RESULTS: In the acute ARDS study, Ang-(1-7) led to a significant improvement in oxygenation (PaO2/FiO2 : vehicle 359 ± 86; ALD 436 ± 72; AHD 44 442 ± 56; ANOVA p = 0.007) and reduced white blood cells counts (vehicle 4,519 ± 2,234; ALD 2,496 ± 621; AHD 2,744 ± 119/mm(3); ANOVA p = 0.004). Only treatment with high dose Ang-(1-7) reduced inflammatory cell numbers in BAL (vehicle 127 ± 34; AHD 96 ± 34/ μl; p = 0.033). Interestingly also delayed administration of Ang-(1-7) was effective in reducing injury. In later ARDS, Ang-(1-7) decreased hydroxyproline content (649 ± 202 and 1,117 ± 297 μg/lung; p < 0.05). CONCLUSIONS: Angiotensin-(1-7), decreased the severity of acute lung injury and inflammation induced by combined acid aspiration and high stretch ventilation. Furthermore, continuous infusion of Ang-(1-7) reduced lung fibrosis 2 weeks following acid aspiration injury. These results call for further research on Ang-(1-7) as possible therapy for ARDS.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".