Lowering Cardiac Branched-Chain Keto Acid Levels Enhances Cardiac Glucose Oxidation and Cardiac Efficiency via Enhancing Mitochondrial Insulin Signaling in Heart Failure
Bibliographic record
Abstract
BACKGROUND: Elevated levels of cardiac branched-chain amino acids (BCAAs) and their metabolites, namely branched-chain keto acids (BCKAs), contribute to the development of insulin resistance, contractile dysfunction, and adverse remodeling in the failing heart. However, there is still confusion about whether BCAA or BCKA mediate these detrimental effects in the failing heart. METHODS: Cardiac-specific mitochondrial branched-chain aminotransferase, the enzyme that converts BCAA into BCKA, knockout (BCAT2 − /− ) mice underwent a sham or transverse aortic constriction surgery to induce heart failure. Changes in cardiac function and structure were monitored pre- and posttransverse aortic constriction using echocardiography, and metabolic flux through the tricarboxylic acid cycle was measured by perfusing isolated working hearts with radiolabeled energy substrates. Direct effects of BCAA and BCKA on cell hypertrophy were characterized using phenylephrine-induced cell hypertrophy in differentiated cells. RESULTS: Lowering cardiac BCKA levels in BCAT2 −/− failing hearts increases insulin-stimulated glucose oxidation rates via enhancing mitochondrial protein kinase B and pyruvate dehydrogenase complex activities. Increased glucose oxidation rates in BCAT2 −/− failing hearts enhanced cardiac efficiency by decreasing myocardial oxygen consumption rates. However, cardiac BCAA accumulation was associated with excessive stimulation of the mammalian target of rapamycin signaling and aggravation of adverse cardiac remodeling in BCAT2 −/− failing hearts. As a result, the impact of BCAA accumulation offsets the beneficial effects of lowering cardiac BCKA levels on cardiac insulin sensitivity and cardiac efficiency. CONCLUSIONS: Lowering BCKA levels enhances cardiac glucose oxidation and cardiac efficiency by enhancing mitochondrial insulin signaling. BCAA accumulation worsens adverse cardiac remodeling by exacerbating cardiac mammalian target of rapamycin signaling.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 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 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".