SPECIAL Seminar with J. Christopher Fritton

Speaker:
J. Christopher Fritton, Ph.D.
Assistant Professor
Department of Orthopaedics
New Jersey Medical School
Rutgers University

Title:
Utilizing Mechanics to Better Understand and Build Bone Tissue

Abstract:
The bioenergetics of bone tissue will be discussed from two standpoints, the use of dynamic mechanics analyses to determine the effects of drugs and the dynamic mechanical loading techniques that the speaker has developed over the course of his academic career as a biomedical engineer. The measurement of tissue-level biomechanical properties, including energy-dissipating capacity, may provide information on function and assist in the prediction of tissue failure. In the prevention of bone failure, bisphosphonates are currently the most potent pharmaceutical treatment. These agents are utilized in combating osteoporotic fracture at the hip and spine and are taken by millions. By reducing osteoclast function, bisphosphonates reduce bone turnover, the remodeling process utilized to remove old and damaged tissue. Bisphosphonates are not without side effects, including a small but significant increase in risk for atypical fracture of mid-shaft bone that increases with duration of treatment and indicates a reduction in bone quality. Results will be presented that demonstrate how perturbations of the normal remodeling of cortical bone lead to tissue-level structural and cell alterations that have consequences for the mechanical integrity of bone, including reduced energy-dissipating capacity and resistance to fracture under cyclic loading. These alterations could offer a partial explanation for the association of long-term bisphosphonate treatment with atypical fractures. Mechanobiology techniques seek to improve bone quality, with the eventual goal of further reducing fracture risk in humans. This requires development of in vivo models to tease out the basic aspects of the biological response. Some early models established that bone as a dynamically loaded tissue adapts to cyclic and not static loading, thus meeting bone’s main function. The speaker has developed three models (free whole-body vibration, controlled compression of the mouse tibia, and a mouse model to induce the process of remodeling in response to microdamage of the ulna). These three now constitute the majority of in vivo basic science techniques for studying bone’s response to energetic inputs. Work aimed at adding biochemical energy to the system to allow greater numbers of aging cells to respond in a positive, anabolic, way to dynamic loads will be discussed. The goal of the burgeoning field of mechano-medicine attempts to utilize the bone’s innate ability to respond to functional needs. While bioenergetics is a common thread to all of the work presented the talk will also attempt to illustrate how being open to data and ideas might allow for new thinking and studies to solve biomedical problems.

Bio:
Chris Fritton earned his bachelor’s and master’s degrees in biomedical engineering from Tulane University (New Orleans) in 1988, and 1993, respectively. He worked as a research and design engineer in biomedical engineering and orthopaedics labs at Tulane (’88 – ’94), SUNY Stony Brook (’94 – ’96) and the Hospital for Special Surgery (’96 – ’00) in New York City before completing his Ph.D. in biomedical engineering at Cornell University in 2005. This was followed by a postdoctoral fellowship in the Department of Orthopaedics at Mount Sinai School of Medicine, where he became an instructor. He joined the New Jersey Medical School (NJMS), now part of Rutgers University, in late 2009 as a faculty member in the Department of Orthopaedics and the Graduate School of Biomedical Sciences and is also on the Graduate Faculties of NJIT and Rutgers BME. His expertise is in bone cell and tissue repair mechanisms. Specific research interests are in the biomechanical prediction of fracture risk utilizing novel dynamic tests, combined use of mechanical loading and bioenergetic agents to enhance bone formation, and how drugs and diet (through the microbiome) affect bone quality. He is the co-author of 23 peer-reviewed journal articles with nearly 1400 scholarly citations, over 70 meeting abstracts, two book chapters, patented inventor of smart bracing systems, reviewer for 15 biomedical journals and he served on the editorial advisory board for the Bone Mechanics Handbook (2nd Edition). Dr. Fritton’s university service includes 3 years as the NJMS program director of the joint Ph.D. biomedical engineering program with NJIT. His teaching has been primarily in the areas of research techniques, regenerative medicine, developmental biology and stem cells, and orthopaedic biomechanics (NJIT/Rutgers graduate students and orthopaedic residents). Dr. Fritton’s research has been funded by the National Institutes of Health, NASA and the Revson Foundation.