Abstract 5422: Effect of Age on Expression of AT <sub>1</sub> and AT <sub>2</sub> Receptors and ACE-2, Angiotensin (1–7), Ac-SDKP and Smad-2 Proteins After Acute Reperfused ST-Segment Elevation Myocardial Infarction
Bibliographic record
Abstract
Recent evidence suggests that aging alters the expression of inflammatory cytokines, impairs healing and promotes adverse left ventricular (LV) remodeling after chronic reperfused ST-segment elevation myocardial infarction (RSTEMI). Whether aging alters the expression of angiotensin II type 1 (AT 1 ) and type 2 (AT 2 ) receptors, and angiotensin-converting-enzyme-2 (ACE-2), angiotensin (Ang) (1–7), N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) and Smad-2 proteins early after acute RSTEMI is not known. AT 2 receptors have been implicated in cardioprotection, ACE-2 and Ang (1–7) in the counter-regulatory arm of the renin-angiotensin-system (RAS) and Ac-SDKP in inflammation and collagen synthesis. We hypothesized that aging is associated with downregulation of AT 2 receptors and ACE-2, Ang (1–7), Ac-SDKP and Smad-2 proteins. We compared in-vivo LV remodeling and function (echocardiography/Doppler) and the ex-vivo molecular expression of AT 1 and AT 2 receptors, ACE-2, Ang (1–7) and Ac-SDKP after acute RSTEMI (90 min no-flow ischemia and 120 min reperfusion) in young (group 1, n=12) and old (group 2, n=12) dogs. Compared to group 1 controls, group 2 hearts showed more severe echocardiographic LV remodeling and dysfunction (with lower ejection fraction, larger volumes and more diastolic dysfunction, infarct expansion and thinning). In addition, group 2 hearts showed no change in AT 1 receptor protein and decrease in AT 2 receptor protein and ACE-2, Ang (1–7), Ac-SDKP and Smad-2 proteins in the reperfused ischemic zone. The findings suggest that aging is associated with changes in proteins in the regulatory as well as the counter-regulatory arm of the RAS during acute RSTEMI. The age-related downregulation of AT 2 receptors, ACE-2, Ang (1–7), Ac-SDKP and Smad-2 may contribute to the more severe LV remodeling and dysfunction after acute RSTEMI. Targeting these proteins early during reperfusion may improve outcome in acute RSTEMI.
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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) | 0.003 | 0.001 |
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".