Examining the Relationship Between Whole Body Resting Metabolic Rate and the Efficiency of SR Ca2+ Handling in Human Skeletal Muscle
Bibliographic record
Abstract
The purpose of this study was to investigate whether skeletal muscle sarcoplasmic reticulum (SR) Ca2+ transport efficiency and expression levels of major SR Ca2+ regulatory proteins are associated with resting metabolic rate (RMR) in humans. Twenty five healthy and weight stable participants with mean age, height and weight of 22±3.6 years, 174.6±8.0 cm and 72.8±21 kg respectively, were recruited for the study. RMR was calculated using the Weir equation based upon measures of VO2 and VCO2, which were collected using the Vmax breath by breath indirect calorimetry system. Ca2+-ATPase activity, Ca2+ uptake and Ca2+ leak analyses were performed in vitro on homogenates that were prepared from vastus lateralis muscle biopsies. Ionophore (IONO) ratio was assessed by measuring Ca2+-ATPase activity in the presence and absence of Ca2+ Ionophore. The coupling ratio, a measure of SR Ca2+ transport efficiency, was calculated by taking the ratio of Ca2+ uptake to Ca2+-ATPase activity. Expression levels of the major SR Ca2+ regulatory proteins, including SERCA1a, SERCA2a, phospholamban (PLN), and calsequestrin (CSQ) were assessed using Western blotting techniques. Pearson correlation coefficient analysis demonstrated a weak but significant negative correlation between coupling ratio and RMR (r2= 0.2108, p =0.0240). Content of the SR Ca2+ regulatory proteins, IONO ratio and Ca2+ leak were not found to be significantly related to either RMR or coupling ratio, with the exception of the ratio of SERCA1a to SERCA2a, which showed a weak but significant positive relationship with RMR (r2=0.1781, p=0.0400). Thus, the relationship between coupling ratio and RMR is not influenced by Ca2+ leak, SERCA pump efficiency or the SR Ca2+ regulatory proteins. Overall, these results suggest that the efficiency of SR Ca2+ transport is weakly related to whole body RMR. Further analysis is needed to assess this relationship, and to determine which SR Ca2+ handling properties are influencing the relationship between coupling ratio and RMR.
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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 | 0.001 |
| 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 | 0.000 |
| 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".