Mechanical Ventilation–induced Diaphragm Disuse in Humans Triggers Autophagy
Bibliographic record
Abstract
RATIONALE: Controlled mechanical ventilation (CMV) results in atrophy of the human diaphragm. The autophagy-lysosome pathway (ALP) contributes to skeletal muscle proteolysis, but its contribution to diaphragmatic protein degradation in mechanically ventilated patients is unknown. OBJECTIVES: To evaluate the autophagy pathway responses to CMV in the diaphragm and limb muscles of humans and to identify the roles of FOXO transcription factors in these responses. METHODS: Muscle biopsies were obtained from nine control subjects and nine brain-dead organ donors. Subjects were mechanically ventilated for 2 to 4 hours and 15 to 276 hours, respectively. Activation of the ubiquitin-proteasome system was detected by measuring mRNA expressions of Atrogin-1, MURF1, and protein expressions of UBC2, UBC4, and the α subunits of the 20S proteasome (MCP231). Activation of the ALP was detected by electron microscopy and by measuring the expressions of several autophagy-related genes. Total carbonyl content and HNE-protein adduct formation were measured to assess oxidative stress. Total AKT, phosphorylated and total FOXO1, and FOXO3A protein levels were also measured. MEASUREMENTS AND MAIN RESULTS: Prolonged CMV triggered activation of the ALP as measured by the appearance of autophagosomes in the diaphragm and increased expressions of autophagy-related genes, as compared with controls. Induction of autophagy was associated with increased protein oxidation and enhanced expression of the FOXO1 gene, but not the FOXO3A gene. CMV also triggered the inhibition of both AKT expression and FOXO1 phosphorylation. CONCLUSIONS: We propose that prolonged CMV causes diaphragm disuse, which, in turn, leads to activation of the ALP through oxidative stress and the induction of the FOXO1 transcription factor.
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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 | 0.001 | 0.001 |
| 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) | 0.000 | 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".