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A Reduction in Cardiac Function Precedes Structural Adaptations in Experimental Spinal Cord Injury
Author(s) -
Fossey Mary,
PoormasjediMeibod MaliheSadat,
Hayes Brian,
Erskine Erin Laurel,
Azad Reathm K,
Granville David James,
Ramer Matt Steven,
West Christopher Roy
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.831.7
Subject(s) - medicine , spinal cord injury , cardiology , atrophy , spinal cord , cardiac function curve , stroke volume , heart rate , anesthesia , blood pressure , heart failure , psychiatry
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 .