Hypoxia regulated expression of erythropoietin in cultured myoblasts and myotubes (1102.35)
Bibliographic record
Abstract
Erythropoietin (EPO) is responsible for supporting the growth and development of red blood cells. EPO is produced mainly by the kidney and its expression is regulated by hypoxia. Several studies have assessed the ability of skeletal muscle to produce EPO, using whole muscle biopsies, and have observed conflicting results. Here, cell culture, RT‐PCR, and flow cytometry were used. The objective was to determine if myoblasts and myotubes were capable of expressing EPO, how its expression might be regulated, and if skeletal muscle was capable of supporting erythropoiesis in vitro. qPCR analysis demonstrated positive expression of EPO in myoblasts and myotubes. EPO expression was not modulated by physiological variables common to working muscle such as mechanical stimulation, pH, or temperature. Hypoxia, however, increased EPO expression in myoblasts by 2.2 fold (p < 0.05) and myotubes by 1.5 fold (p < 0.05). When myoblasts were conditioned with hypoxia, media taken from them was able to support erythropoiesis in bone marrow cultures. 72 hours after treatment with hypoxic myoblast conditioned media, Ter‐119 positive cells in bone marrow culture were increased by 20% (p < 0.05). These results suggest that both myoblasts and myotubes are capable of expressing EPO and do so in a hypoxia dependent manner. As well, these results lend support to studies that have observed increases in circulating levels of EPO following endurance exercise interventions, where skeletal muscle oxygen saturation is known to drop to hypoxic levels.
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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 | 0.001 |
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".