11:12 a.m., March 23, 2010----Christopher Price, research assistant professor in the Department of Mechanical Engineering at the University of Delaware, has won the Orthopaedic Research Society's New Investigator Recognition Award for his groundbreaking work on fluid flow in bone. The first-place award was conferred at the society's annual meeting, held in New Orleans from March 6-9.
According to Liyun Wang, assistant professor of mechanical engineering at UD and Price's postdoctoral adviser from 2008 to 2010, “This is a very prestigious award, and it's rarely granted to researchers in engineering. Most past recipients have been in biological or medical sciences.”
Co-authored with Wang and UD doctoral students Xiaozhou Zhou and Wen Li, the research provides the first concrete evidence of fluid flow in mechanically loaded bone samples -- a critical piece in the puzzle of bone metabolism and mechanotransduction, the processes by which cells convert mechanical stimuli into biological and chemical activity.
Price hopes that the work will contribute to a better understanding of what causes people to gain or lose bone mass. With osteoporosis a major health threat for an estimated 44 million Americans, or 55 percent of people 50 years of age and older, the work has important implications for individual and public health. In addition, millions of other people, including children, suffer from bone fragility due to genetic disorders such as osteogenesis imperfecta.
The theory that load-induced fluid flow is the primary mechanism of transport of nutrients and signaling molecules between the blood supply and osteocytes -- cells within the bone that transmit signals directing bone deposition, resorption, and remodeling -- was first postulated more than 30 years ago.
“The basic premise behind the theory,” Price explains, “is that bone is like a very stiff sponge. When you load bone, or squeeze it, fluid flows out, and when you release it, fluid flows in. The problem is that no one has been able to prove the theory -- studies done to date have either been computationally based or provided evidence through tracer distribution rather than direct evidence.”
Using a novel experimental setup that integrates a loading apparatus with a confocal microscope, Price and his colleagues have been able to record the actual convective transport around osteocytes when bone is subjected to well-controlled mechanical loading.
In addition, the team has incorporated their experimental results into a mathematical model that has the correct anatomical features of the cells and the channels within the bone, known as the lacunar-canalicular system, so that they can gain a better understanding of the transport process and make accurate predictions of the velocities of fluid and solute flows when bone is exposed to various everyday activities. Current research has found that these physical flow signals trigger the downstream biochemical responses of the cells in terms of gene and protein expressions.
“This combined experimental and theoretical approach enables us, as engineers, to provide biologists with quantitative data to enable more accurate in vitro testing,” Price says. “We can tell other researchers how much force to apply to cells when they want to mimic a subject walking versus running. Further, once we understand the biology of osteoporosis and other forms of fragility, we can begin to design rational therapies for these diseases.”
Trained as both an engineer and a biologist, Price is providing a bridge between the two fields. He earned his undergraduate degree in biomedical engineering at Boston University and his doctorate in biomedical sciences at the Mt. Sinai School of Medicine.
“Chris joined my group in 2008,” Wang says. “It is amazing that he has accomplished this much in just two years. He is a thorough, detail-oriented, and motivated young investigator.”
“The fact that Chris and his co-authors, including Prof. Wang, were selected for this award demonstrates that the biomedical program in the Department of Mechanical Engineering at the University of Delaware is an internationally recognized research group,” says chairperson Anette Karlsson.
The research was supported by an R01 grant awarded to the research team led by Wang. The work also won the Webster Jee Young Investigator Award for contributions to musculoskeletal research from the Chinese Hard Tissue Society.
Article by Diane Kukich