Mitochondrial functional alterations in COPD locomotor muscle are independent of cachexia and fiber type shift
Bibliographic record
Abstract
Although prior studies have examined mitochondrial function in COPD muscle, none have compared cachectic versus non-cachectic patients, nor have they compared patients with type II shift versus those who are not shifted. Since mitochondrial dysfunction is thought to contribute to muscle atrophy in COPD, we hypothesized that mitochondrial alterations would be greater in cachectic patients. Similarly, we hypothesized that an impaired muscle oxidative capacity, an increase in mitochondrial ROS emission and an insensitivity to permeability transition would be greater in COPD patients with a shift towards greater type II fiber abundance. Strikingly, our results show that although there is a greater reduction in mitochondrial oxidative capacity in cachectic patients, both ROS emission and sensitivity to permeability transition are similar in cachectic versus non-cachectic patients. In regard to our second hypothesis, whereas there were no differences in oxidative capacity or ROS emission between COPD patients with type II fiber shift, a lower sensitivity to permeability transition was seen in COPD patients with a type II fiber shift. As such, our analysis reveals that fiber type shift per se is unlikely to account for the lower muscle oxidative capacity and increase in mitochondrial ROS emission seen in COPD muscle, but could explain the lower sensitivity to permeability transition. Overall, our results suggest that mitochondrial involvement in COPD is primarily to reduce oxidative capacity of COPD muscle, but as some changes are dissociated from a fiber type shift, these changes may constitute dysfunction even if they are not contributing to development of cachexia.
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 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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".