Date on Master's Thesis/Doctoral Dissertation

5-2017

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Anatomical Sciences and Neurobiology

Degree Program

Anatomical Sciences and Neurobiology, PhD

Committee Chair

Magnuson, David

Committee Co-Chair (if applicable)

Brueckner-Collins, Jennifer

Committee Member

Brueckner-Collins, Jennifer

Committee Member

LeBlank, Amanda

Committee Member

Keller, Bradley

Committee Member

Howland, Dena

Author's Keywords

spinal cord injury; cardiovascular; exercise

Abstract

There is a general consensus that the level and the severity of spinal cord injury (SCI) impacts chronic cardiac abnormalities such that high thoracic and cervical SCI are the most severely affected. Furthermore, the extreme degree of immobility/inactivity experienced by the persons with SCI has implications on cardiac decline. Yet it has been difficult to separate the relative contributions of the decentralized autonomic nervous system (ANS) and the immediate and profound inactivity to chronic cardiac abnormalities. As such, this body of work sought to characterize a contusion SCI that results in persistent CV dysfunction. Echocardiography, Dobutamine stress echocardiography and pressure volume assessments were utilized to gain insights into structural remodelling and functional reserve following injury. Passive hind-limb cycling (PHLC) and swim (SWIM) training were employed to potentially reverse the observed cardiac decline. We also controlled spontaneous activity by limiting or increasing the amount of space available for animals to move to further our understanding of the effects of immobility/inactivity on SCI induced cardiac dysfunction. Our findings show that SCI disruption of the ANS results in diminished systolic function. Furthermore, we show that when appropriate interventions are implemented acutely cardiac function can be favourably influenced. However, when spontaneous activity is hindered extreme inactivity compound the initial SCI and further exacerbates cardiac decline.

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