Grant: Project Grant - PA: Sex, Gender & Health Research - Integration & Innovation

A stroke occurs when blood flow to the brain is interrupted. Many stroke survivors have permanent problems with walking due to inadequate treatment. We are studying how optimal nutrition can be used to assist with recovery of the brain and affected leg muscles, and whether this changes with aging or sex. This is important because ~12-19% of elderly stroke patients already suffer from poor protein-energy nutrition at the time of stroke. Because of multiple challenges caused by the stroke (e.g. difficulty in swallowing and feeding oneself, depression, or mobility problems), even more patients develop malnutrition later. By 1 week after stroke, 20-35% of patients are affected, and this rises to ~35-49% during the rehabilitation period. We use surgery to cause a stroke in rats in a part of the brain that is important for normal walking. Animals are fed varying diets before and/or after the stroke. This includes diets deficient in protein and energy, nutritionally adequate diets, and high protein treatment diets. Brain damage is measured by the size of the damaged area. The ability of the rat to walk skillfully is measured with behavioural tests. For example, animals are tested while walking across a horizontal ladder (an uneven surface). The rung pattern can be changed to provide varying challenge. A regular pattern allows trained rats to know ahead of time where the rungs are and to learn a specific walking pattern; this is like humans walking in a familiar environment. To increase the challenge, a new and uneven pattern is presented. This is like the "real world" that presents a variety of unpredictable obstacles requiring more complex changes in how one walks. We also do lab testing on brains, leg muscles, and blood samples to tell us how these nutritional conditions and treatments affect recovery. Our long-term goal is to develop new approaches to nutritional care of patients after stroke that can work alongside rehabilitation to improve recovery.