Abstract 13389: Critical Role of Electron Leak From Mitochondrial Electron Transport Chain Complex I in Oxygen Sensing in the Rabbit Ductus Arteriosus
Bibliographic record
Abstract
Introduction: The ductus arteriosus (DA) allows placentally oxygenated blood to bypass the non-ventilated fetal lungs and enter the systemic circulation. The fetus’ systemic pO 2 is ~40 mmHg, maintaining the DA in a state of hypoxic vasodilation. As pO 2 rises, with the first breath, the DA constricts and achieves functional closure within minutes. We have identified a mitochondrial O 2 -sensor controlling functional closure within DA smooth muscle cells (DASMC). Increased pO 2 leads to increased reactive oxygen species (ROS) production by complexes I and III of the electron transport chain (ETC). These ROS are diffusible signaling molecules and inhibit redox sensitive potassium channels causing DASMC depolarization and vasoconstriction. We propose this reflects electron leak from ETC complexes. Using the term rabbit model, we investigated the differential function of ETC I vs III complex-specific electron leak suppressors (S1QEL vs S3QEL) on vascular tone in DA rings. Methods: DA’s from term rabbits (n=11 rabbits, n=29 individual DA rings) were mounted on a force transducer at ~800 mg in Krebs at a PO 2 of ~40mmHg. DA’s were subject to varying pO 2 levels (from 35-155 mmHg) and at peak O 2 constriction were treated with ETC leak suppressors, ETC complex inhibitors or vehicle controls (DMSO). Results: Exposure to normoxia caused an average 1100±62 mg increase in DA tension. S1QEL (50 μM) caused an average 20.9±6.2% reduction in DA tension (n=8) whereas S3QEL (100 μM) only reduced DA tension by 4.4±2.2% (n=4). Rotenone (complex I inhibitor) and antimycin A (complex III inhibitor) also relaxed the DA while vehicle had minimal effect (-2.6±1.5%). Conclusions: Electron leak from complex 1, but not complex 3, is implicated in DA O 2 -sensing.
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How this classification was reachedexpand
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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 | 0.000 |
| 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".