Woodruff School of Mechanical Engineering
Faculty Candidate Seminar
The role of tissue properties and cellular metabolism in bone structure and function
Dr. Jacqueline Cole
University of Michigan
Monday, April 29, 2013 at 11:00:00 AM
MRDC Building, Room 4211
Age-related changes in bone tissue contribute to skeletal fragility, yet clinical assessment tools remain insufficient to assess tissue quality, particularly the material strength, material heterogeneity, and chemical composition. In human vertebral bone, clinical measurements of bone density explain only about 50% of the variability in apparent tissue modulus and ultimate strength. Architecture-based finite element models for these specimens reveal that the heterogeneity in tissue mineralization, and thus in tissue modulus, is important for predicting structural integrity. In addition, the chemical composition (e.g., mineral/matrix ratio and mineral crystallinity from Raman spectroscopy) of these specimens correlates with tissue modulus and hardness as measured by nanoindentation, which are indicators of fracture toughness. In vivo composition measurements may improve predictions of fracture risk but are not currently available for clinical use. Recent advances in fiber optic Raman probes, however, allow the noninvasive measurement of bone tissue composition in live animal models. At the foundation of these structural and material properties lies the dynamic regulation of the cells governing bone maintenance, adaptation, and repair critical to skeletal health. Cellular metabolism drives the capacity of bone cells to respond to environmental cues, such as oxygen tension, as evidenced by greater oxygen sensitivity in bone cells from rats with high vs. low intrinsic aerobic capacity, as well as a differing skeletal phenotype in general. These studies reveal questions about the role of oxygen utilization and metabolism in skeletal maintenance, adaptation and repair, which may depend on mitochondria number and function, as well as bone-vascular interactions.
Jacque Cole is a postdoctoral fellow in the Orthopaedic Research Laboratory at the University of Michigan. Her current research focuses on characterizing the impact of aerobic metabolism on whole bone mechanics, bone tissue properties, and cellular activity and function. She received her Ph.D. in Mechanical Engineering at Cornell University, where she examined the role of architecture and tissue properties in the structural integrity of human vertebral cancellous bone. Dr. Cole received a NIH Ruth L. Kirchstein National Research Service Award to develop technology and instrumentation for in vivo Raman spectroscopy of bone tissue. She received the Harold M. Frost Young Investigator Award from the Sun Valley Workshop on Musculoskeletal Biology, the Young Investigator Award from the American Society for Bone and Mineral Research, and the New Investigator Award from the International Conference on the Chemistry and Biology of Mineralized Tissues.
Refreshments will be served.