Grant: Catalyst Grant: Musculoskeletal Health and Arthritis

Bones are dynamic living organs which undergo continual change throughout our lives. An internal process of tissue renewal, called remodeling, removes old microscopic packets of bone and replaces them with new bone in a highly coordinated manner. Imbalance in this process, where the bone removed is not fully replaced, is the root cause of osteoporosis. This disease afflicts millions of Canadians and costs our healthcare system billions. Strategies for preventing or combating osteoporosis must focus on tipping the balance of remodeling towards more formation and less destruction of bone within each discrete remodeling event. However, before achieving that goal it is necessary to closely characterize the remodeling process and have a platform for assessing the effects of treatments. To date, it has not been possible to directly observe and track individual remodeling events due to a number of factors including the small size of the structures involved, the large radiation dose necessary to detect them with X-ray based techniques and the fact that the small animals generally used in bone research (mice and rats) do not exhibit remodeling within their compact outer cortical bone. The current proposal seeks to address these shortcomings through the application of an innovative imaging technique (X-ray phase contrast), which enhances image quality without increasing radiation dose, to an animal which remodels its compact bone in a manner similar to humans, the rabbit. The application of this imaging technique to a rabbit model of osteoporosis will enable, for the first time, direct 3D and even 4D (3D over time) tracking of remodeling events in living bone. In other words, we will have the capacity to track the very pores of osteoporosis as they form. This will create a powerful new tool for future research targeting the improvement of strategies for the prevention and treatment of osteoporosis.