High levels of fatty acids increase contractile function of neonatal rabbit hearts during reperfusion following ischemia
Bibliographic record
Abstract
In the neonatal heart the transition from using carbohydrates to using fatty acids has not fully matured and oxidative metabolism/ATP generation may be limiting contractile function after ischemia. This study tested the hypothesis that increasing fatty acid availability increases recovery of left ventricular (LV) work by increasing palmitate oxidation, tricarboxylic acid (TCA) cycle activity, and ATP generation. Isolated working hearts from 7-day-old rabbits were perfused with Krebs solution containing low (0.4 mM) or high (2.4 mM) palmitate and 5.5 mM glucose. Hearts were subjected to 35-min global ischemia before 40-min reperfusion, and rates of glycolysis, glucose oxidation, and palmitate oxidation were assessed. LV work was similar before ischemia but was greater during reperfusion in hearts perfused with 2.4 mM palmitate compared with hearts perfused with 0.4 mM palmitate [6.98 +/- 0.14 (n = 15) vs. 3.01 +/- 0.23 (n = 16) mJ.beat(-1).g dry wt(-1); P < 0.05]. This was accompanied by increased LV energy expenditure during reperfusion [35.98 +/- 0.16 (n = 8) vs. 19.92 +/- 0.18 (n = 6) mJ.beat(-1).g dry wt(-1); P < 0.05]. During reperfusion the rates of palmitate oxidation [237.5 +/- 28.10 (n = 7) vs. 86.0 +/- 9.7 (n = 6) nmol.g dry wt(-1).min(-1); P < 0.05], total TCA cycle activity [2.65 +/- 0.39 (n = 7) vs. 1.36 +/- 0.14 (n = 6) micromol acetyl-CoA.g dry wt(-1).min(-1); P < 0.05], and ATP generation attributable to palmitate oxidation [26.6 +/- 3.1 (n = 7) vs. 12.6 +/- 1.7 (n = 6) micromol.g dry wt(-1).min(-1); P < 0.05] were greater in hearts perfused with 2.4 mM palmitate. These data indicate that the neonatal heart has decreased energy reserve, and, in contrast to the mature heart, increasing availability of fatty acid substrate increases energy production and improves recovery of function after ischemia.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".