The objective of this award is to understand how the pressure and motion of bone marrow within the trabecular - or spongy - bone in the hip are affected by forces during walking. The bone marrow in the hip is one of the main sites where hematopoietic (blood forming) and mesenchymal (skeletal tissue forming) stem cells are found in adults, although their numbers decline with age. Studies have demonstrated that mesenchymal stem cells, while few in number, are highly sensitive to mechanical stimulation, but the types and magnitudes of stimuli they experience in the body are largely unknown. An experimental study will be conducted to measure the pressure at different locations within the hip during simulated walking. Data from the experiments will be incorporated into computational models to estimate the pressure throughout the bone. A second set of models will employ these calculated pressures to determine the motion of the marrow at the microscopic scale, and the distribution of mechanical stimuli in the marrow.
If successful, these studies will provide insight into the mechanical environment of bone marrow and the range of stresses that are imparted to adult stem cells on a daily basis. These results will improve interpretation and design of cell culture experiments and tissue engineering constructs by providing baseline stimulus levels. They may also provide insight into changes in the bone marrow, such as the decline in the mesenchymal stem cell population with age. Finally, the computational models can be used to predict the behavior in response to abnormal loading or disease conditions. To extend the impact of this project to the wider community, a high-school teacher will participate in the research, and the project team will help them incorporate the methods and findings into courses and projects.
