Grant: CIHR Fellowship

(up to 4.6 million). Many of these costs are used to treat stroke and heart disease, which are the main causes of illness and death of people with a SCI. In fact, people with SCI are 3-4 times more likely to suffer a stroke compared to the general population. Also, the majority of people with a SCI have a decrease in cognitive function. Both the risk of stroke and reduced brain function are related to poor health of the blood vessels in the brain. Bouts of high blood pressure are one possible cause for poor blood vessel health. People with a SCI have been shown to have many bouts of high blood pressure on a daily basis. Understanding if and how these bouts of high blood pressure injure the brain blood vessels is very important so that we can prevent them, and their dangerous side effects. Furthermore, exercise has the ability to reduce the severity of the bouts of high blood pressure in those with SCI, and may help improve the health of their brains. The overall objective of this study is to understand how bouts of high blood pressure following a SCI affect the health of the brain. We also plan to test if routine exercise participation can improve health of the brain after SCI, by reducing the severity of high blood pressure bouts. In people with SCI, constipation causes blood pressure to rise very high. We will make this happen daily in rats by slightly inflating a balloon in their colon. After 4 weeks, and after 12 weeks, we will look at the brain blood vessels using a laser camera to see if they have become unhealthy. Thinking ability will also be tested. Last, we will look at blood vessels of the brain and the brain tissue itself to see if there were any changes in health of these areas. In another group of animals, also completing 4 and 12 weeks of the "simulated constipation", passive exercise will be completed concurrently, and we will test if the exercise is able to improve brain health in animals by reducing these high blood pressure episodes.