Chronic Inhibition of Pyruvate Dehydrogenase in Heart Triggers an Adaptive Metabolic Response
Bibliographic record
Abstract
Diabetic cardiac dysfunction is associated with decreased rates of myocardial glucose oxidation (GO) and increased fatty acid oxidation (FAO), a fuel shift that has been shown to sensitize the heart to ischemic insult and ventricular dysfunction. We sought to evaluate the metabolic and functional consequences of chronic suppression of GO in heart as modeled by transgenic mice with cardiac-specific overexpression of pyruvate dehydrogenase kinase 4 (myosin heavy chain (MHC)-PDK4 mice), an inhibitor of pyruvate dehydrogenase. Hearts of MHC-PDK4 mice were shown to exhibit an insulin-resistant substrate utilization profile, characterized by low GO rates and high FAO flux. Surprisingly, MHC-PDK4 mice were not sensitized to cardiac ischemia-reperfusion injury despite a fuel utilization pattern that phenocopied the diabetic heart. In addition, MHC-PDK4 mice were protected against high fat diet-induced myocyte lipid accumulation, likely related to increased capacity for FAO. The high rates of mitochondrial FAO in the MHC-PDK4 heart were related to heightened activity of the AMP-activated protein kinase, reduced levels of malonyl-CoA, and increased capacity for mitochondrial uncoupled respiration. The expression of the known AMP-activated protein kinase target, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a master regulator of mitochondrial function and biogenesis, was also activated in the MHC-PDK4 heart. These results demonstrate that chronic activation of PDK4 triggers transcriptional and post-transcriptional mechanisms that re-program the heart for chronic high rates of FAO without the expected deleterious functional or metabolic consequences.
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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) | 0.000 | 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 | 0.001 |
| 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".