Matrix metalloproteinase-2 mediates cytokine-induced myocardial contractile dysfunction
Why this work is in the frame
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Bibliographic record
Abstract
OBJECTIVE: Pro-inflammatory cytokines depress myocardial contractile function by enhancing peroxynitrite production, yet the mechanism by which peroxynitrite does this is unknown. As matrix metalloproteinases (MMPs) can be activated by peroxynitrite and can proteolytically cleave troponin I in hearts, we determined whether this occurs in cytokine-induced myocardial dysfunction. METHODS: Isolated working rat hearts were perfused with buffer containing interleukin-1 beta, interferon-gamma, and tumor necrosis factor-alpha. RESULTS: Cytokines induced a marked decline in mechanical function during 60-120 min of perfusion. This decline was accompanied by increased myocardial inducible NO synthase activity and perfusate dityrosine (a marker of peroxynitrite), compared to control hearts. Before the decline in mechanical function there was enhanced MMP-2 activity in the perfusate. This was accompanied by decreased tissue levels of MMP-2, tissue inhibitor of matrix metalloproteinases-4 and troponin I in cytokine-treated hearts. The collagen content of the heart was not affected by cytokine treatment. A neutralizing anti-MMP-2 antibody or the MMP inhibitors Ro31-9790 or PD166793 attenuated the decline in myocardial function. Moreover, the MMP-2 antibody prevented the decline in myocardial MMP-2 and troponin I levels. CONCLUSIONS: Myocardial contractile dysfunction caused by pro-inflammatory cytokines results in MMP-2 activation and a decline in tissue inhibitor of matrix metalloproteinases-4 in the heart. Troponin I is also a target for the proteolytic action of MMP-2 during acute heart failure triggered by pro-inflammatory cytokines. Inhibition of MMPs may be a novel pharmacological strategy for the treatment of acute inflammatory heart disease.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.007 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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 it