The Scaling of Bone Strength During Growth and Aging: Is Bigger Better?
Abstract: Over a lifespan of approximately 70 years, bone withstands millions of loading cycles from muscle forces with incredible resilience to fatigue. However, the mechanisms driving bone formation, organization, and strength are yet to be fully resolved. What is known is that the mechanical cues for bone development in mammals are a result of the dynamic muscle and joint forces experienced during locomotion, and less influenced by static gravitational forces. Therefore, the adaptation of bone to accommodate increased external forces occurs in a specific manner. That is—it doesn’t just get bigger—it has a specific preferential distribution of material in order to maintain efficient mechanical competency. In this talk, I will present our recent efforts to understand the three-dimensional mechanics of bone during growth and aging. First, using a murine model of growth, we investigated gait-driven determinants of spatially heterogeneous strain within the tibia using longitudinal imaging and multi-scale computational models. We also investigated these allometric relationships in equine bone to determine if these hold true for larger animals. Next, I will present a computational assessment of bone strain energy in older human bone samples. Here we aim to identify whether increased strain energy is characterized by morphological features and associated with specific phases of cellular activity during bone remodeling. Together, this information can provide structural and cellular cues indicative of bone strength that can be used as biomarkers for bone health during exercise-based interventions.
Mariana Kersh is an assistant professor of mechanical science and engineering at Illinois and the director of the Tissue Biomechanics Laboratory. She holds degrees in English (B.S.), Mechanical Engineering (B.S.,M.S.) and Material Science (Ph.D.). Her research focus is on the structure-mechanical function of orthopedic tissues during development as well as the progression of musculoskeletal diseases such as osteoporosis. She was a recipient of the Australia-New Zealand Orthopedic Research Society Early Career Award and her work has been funded by the National Science Foundation and several biomedical industry sponsors.