Abstract 17219: Increased Aortic Stiffness Following Intrauterine Exposure to Chronic Hypoxia in Rats
Bibliographic record
Abstract
Background: We have previously demonstrated in rats that fetal hypoxia is associated with altered left ventricular (LV) diastolic function beginning in early postnatal life (2 weeks). In the present study we hypothesized that intrauterine hypoxia exposure alters aortic stiffness which may contribute to the evolution of myocardial dysfunction after birth. Methods: Six pregnant rats were exposed to hypoxic conditions (11.5% FiO2) from E15-21and 3 were maintained in normoxic conditions. After delivery, 4 neonatal rats from each group were examined longitudinally at day 1, 3, and week 1, 2, 4, 8 for changes in aortic stiffness. Pups were anesthetized by face mask with 1.5% isoflurane. Aortic stiffness was assessed by measuring the pulse wave velocity (PWV) in the ascending aorta at 3 points: 1. Proximal to the branch of the first brachiocephalic artery 2. At the level of the diaphragm and 3. Just above the aortic bifurcation into the iliac arteries. T1 was the time interval from the peak of the R wave by ECG to onset of flow in the ascending aorta and T2 from peak of the R wave to onset of flow in either the mid aorta or distal aorta. The distance from the suprasternal notch to the subxiphoid process and to the anterior superior iliac spine was measured in each animal. The PWV was calculated using the following equation: [distance/(T2-T1)]. Three consecutive tracings were assessed and the PWV averaged for each study. Statistical analysis was performed using a 2-way ANOVA. Results: In pups exposed to fetal hypoxia, PWV was significantly increased (p≤0.001) compared to controls at day 1 (4.8±1.5 vs. 2.3±0.2 m/s), day 3 (5.5±0.3 vs. 2.6±0.1 m/s) and week 1 (4.4±0.4 vs. 2.8±0.1 m/s). Interestingly, there was an interaction of time and fetal exposure (p=0.006) whereby PWV values converged from weeks 2 - 8 such that fetal exposure to hypoxia no longer had an effect. No correlation was found between LV diastolic function parameters and aortic PWV in the fetal hypoxia rats at any postnatal age. Conclusion: Prenatal exposure to hypoxia was associated with increased aortic stiffness during early development. The lack of a relationship between LV diastolic function and aortic stiffness could suggest these represent independent effects of fetal hypoxia exposure.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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 | 0.000 |
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".