A Reduction in Cardiac Function Precedes Structural Adaptations in Experimental Spinal Cord Injury
Bibliographic record
Abstract
Introduction Chronic high‐thoracic spinal cord injury (SCI) is associated with systolic dysfunction, cardiomyocyte atrophy and the upregulation of major proteolytic pathways in the heart. How such dysfunction manifests with time is presently unknown. Methods Male Wistar rats underwent complete SCI at the 3 rd thoracic spinal level (T3‐SCI; n=10) or dorsal durotomy (SHAM; n=5). T3‐SCI rats were terminated at different time points: three days post‐SCI (3‐day SCI; n=5) or seven days post‐SCI (7‐day SCI; n=5). SHAM rats were terminated at seven days post‐durotomy. On termination day, prior to euthanasia, left‐ventricular (LV) catheterization was performed to assess cardiac function. Additionally, cardiac tissue was collected for histological analysis to quantify cardiomyocyte dimensions (standardized to femur length). Results Relative to SHAM, T3‐SCI rats at both 3‐day and 7‐day post‐SCI exhibited reduced stroke work (SW; p=0.036), load‐independent contractile function (inferred with end‐systolic pressure‐volume relationship, ESPVR; p=0.0013) and maximal rate of LV systolic pressure increment (dP/dt max ; p=0.0070). The maximal rate of LV relaxation (i.e. ‐dP/dt min ; p=0.019) was reduced at 3‐day and 7‐day post‐SCI vs. SHAM; however, tau (time constant of isovolumic relaxation) was not different (p=0.15). There were no differences for any functional indices between 3‐day vs. 7‐day SCI. Histological analysis of cardiomyocytes indicates no significant differences in length and width in SCI groups vs. SHAM (length p=0.20; width p=0.24). Conclusion Systolic cardiac function decreased significantly in both 3‐day and 7‐day SCI rats vs. SHAM. This indicates a rapid onset of cardiac dysfunction following T3‐SCI. Cardiomyocyte atrophy was not present in either 3‐day or 7‐day SCI rats, implying a reduction in cardiac function precedes structural remodeling. Support or Funding Information Heart and Stroke Foundation of Canada (HSFC), International Collaboration on Repair Discoveries (ICORD) and Blusson Integrated Cure Partnership (BICP). This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".