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Neuroprosthetic baroreflex controls hemodynamics after spinal cord injury

Team Members:
  • Aaron Phillips, University of Calgary
  • Barbara Turnbull Foundation for Spinal Cord Research

Project Overview

Spinal cord injury (SCI) leads to blood pressure instability that threatens survival, impairs neurological recovery, increases the risk of cardiovascular disease, and reduces quality of life. Blood pressure instability occurs after SCI as the brain can no longer activate the sympathetic nervous system, preventing the blood pressure stabilizing system known as the baroreflex from effectively functioning. Epidural electrical stimulation was known to activate circuits responsible for walking after SCI. In my paper, we used epidural electrical stimulation to activate and control the sympathetic nervous system in closed-loop. This system functions as a ‘neuroprosthetic baroreflex’. We developed a new preclinical model of blood pressure instability after SCI. This model allowed us to understand the anatomical arrangement and dynamics of sympathetic circuits within the spinal cord in context of blood pressure control. We used 

this knowledge to develop clinical-grade epidural electrical stimulation hardware targeting a new region within the spinal cord that we discovered houses the key circuits responsible for blood pressure control – termed the hemodynamic hotspot. We engineered this hardware to recapitulate the natural dynamics of the sympathetic nervous system that are lost after spinal cord injury. The neuroprosthetic baroreflex can stabilize blood pressure to user-defined levels for extended periods of time in the acute and chronic phases of SCI. We are now completing a series of clinical trials to make the neuroprosthetic baroreflex a widely available therapy.