Time Course of Structural and Functional Adaptations of Mesenteric Resistance Vasculature after High Thoracic Spinal Cord Injury
Bibliographic record
Abstract
Background Spinal cord injury (SCI) disrupts autonomic pathways and consequently perturbs cardiovascular homeostasis. Injuries above T6 results in loss of descending sympathetic control of the splanchnic vasculature. Blood pressure regulation is impaired resulting in resting hypotension and episodic hypertension, the latter of which is known as a life threatening condition called autonomic dysreflexia (AD). These fluctuations in arterial blood pressure following SCI may also result in dysfunction and maladaptive remodelling at the level of the splanchnic resistance vasculature. Objective To examine the time course of structural and functional adaptations of resistance mesenteric vasculature in a complete T3 transection rodent model. Design/Method 15 male Wistar rats were randomly assigned to three groups: T3 SCI 1 Week (n=5), T3 SCI 1 Month (n=5), and Uninjured Control (n=5). Functional and structural assessment of primary mesenteric arteries were assessed ex vivo using a pressure myograph system. In addition to vessel morphology and myogenic tone, functional assessment of vasocontractility was assessed using α1 adrenoceptor agonist phenylephrine (PE) and methoxamine (MET). Results Myogenic tone is significantly impaired in the T3 SCI 1 Week and T3 SCI 1 Month groups compared to the Uninjured Control group (p = 0.0212 and p=0.0059, respectively). EC50 values were extrapolated from PE dose response curves and were lower for both the T3 SCI 1 Week and T3 SCI 1 Month groups compared to the Uninjured Control group (p<0.0001 and p=0.0004, respectively). There are no significant differences found between EC50 values determined for MET. Wall thickness is decreased and vessel diameter is increased in the T3 SCI 1 Month group compared to the Uninjured Control group (p=0.0221 and p=0.066, respectively). Conclusion Hypersensitivity to the α1 adrenoceptor agonist PE but not MET suggest deficiency in the reuptake of norepinephrine in resistance mesenteric vasculature. Decreased wall thickness, in addition to an increased vessel diameter may suggest chronic outward hypotrophic remodelling. Support or Funding Information This research was funded by the Canadian Institute of Health Research and the Heart and Stroke Foundation of BC and Yukon.
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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) | 0.002 | 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".