Autonomic dysreflexia and axonal plasticity in sympathetic ganglia following spinal cord injury

Each year, 35 people per million in Canada sustain a spinal cord injury. Apart from the well known motor and sensory dysfunctions, there are a number of autonomic nervous system changes that can occur after spinal cord injury, including bladder, bowel, thermoregulatory, sexual and cardiovascular dysfunctions. These changes significantly affect the overall quality of life of individuals with spinal cord injury. One cardiovascular dysfunction that commonly develops following high spinal cord injury is called autonomic dysreflexia. Autonomic dysreflexia is a life-threatening condition that is characterized by sudden increases in blood pressure triggered by normal touch below the level of injury. These episodes can be extremely uncomfortable for patients as they are often accompanied by pounding headaches, upper body flushing and feelings of anxiety. Furthermore, as these episodes are often triggered by routine daily events, such as catheterization, they can significantly interfere with rehabilitation programs and work schedules. The cause of autonomic dysreflexia is unknown. In her research, Jessica is looking at how spinal cord injury changes sympathetic nerve cells – cells that are involved in regulating blood pressure by speeding up the heart and contracting blood vessels. One possibility is that there are unusual new connections formed between sensory and sympathetic nerve cells after spinal cord injury; so that a normal touch, which did not cause increased blood pressure before injury, is abnormally connected to sympathetic nerve cells after injury, causing increased blood pressure. Ultimately, Jessica hopes her research will help lead to the development of therapeutic strategies to prevent autonomic dysreflexia’s devastating effects on people with spinal cord injury.