Posted May 26, 2009 Atlanta
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Musculoskeletal Biology and Regenerative Medicine Expertise are Keys
When a soldier is wounded during combat, surgeons must focus on reducing infection and reconstructing damaged bone and tissues. Technologies that could improve the repair and regeneration processes are being developed in research laboratories across the country, but they are not being moved quickly enough into military trauma centers.
Organizers of the recently established Georgia Tech Center for Advanced Bioengineering for Soldier Survivability want to change that.
"The goal of the center is to rapidly move new technologies from the laboratory to patients so that we can improve the quality of life for our veterans as they return from the wars the United States is fighting," said center director Barbara Boyan, the Price Gilbert, Jr. Chair in Tissue Engineering at the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.
The center will leverage the expertise of Georgia Tech researchers in musculoskeletal biology and regenerative medicine to quickly move tools that are clinically valuable, safe and effective from laboratories to use in trauma centers. To reduce the amount of time from invention to clinical use, engineers and scientists in the center work in teams that include a clinician with experience in combat medical care and a medical device industry partner.
Support for the center is provided by the Armed Forces Institute of Regenerative Medicine, the U.S. Army Institute of Surgical Research's Orthopedic Trauma Research Program, the U.S. Department of Defense and industry.
Researchers in the center will initially focus on ways to improve the healing of wounds, segmental bone defects and massive soft tissue defects. Traumatic injuries that affect the arms, legs, head and neck require technologies for treatment at the time of injury and in the ensuing days and months.
"These combat injuries are complicated to treat because they are large and typically infected, so even determining when a soldier should be treated for optimal recovery is a challenge," said Boyan, who is also the associate dean for research in Georgia Tech's College of Engineering and a Georgia Research Alliance Eminent Scholar. "It is not known whether a regenerative therapy will be most effective if used immediately following injury or at some later time after scar tissue has been established at the wound site."
By developing models that accurately reflect the complex aspects of injuries sustained by soldiers in combat, the researchers will be able to test assumptions about when to employ specific strategies and how to ensure their effectiveness. The models must also allow them to examine the use of technologies on both male and female patients, and on complex tissues that consist of nerves, a blood supply and multiple cell types.
"Since the processes of bone, vascular and neural formation are naturally linked during normal tissue development, growth and repair, our approach is to harness this knowledge by developing delivery strategies that present the right biologic cues in the right place at the right time to promote functional regeneration of multiple integrated tissues," said associate director of the center Robert Guldberg, a professor in Georgia Tech's Woodruff School of Mechanical Engineering.
To enhance tissue repair and regeneration following a traumatic injury, the researchers are focusing their efforts on stem cells. Even though stem cells have tremendous potential for repairing such defects, effective methods do not yet exist for delivering them to an injury site and of ensuring that they survive and remain at that site long enough to impact the regeneration process.
"Clinicians currently inject stem cells into a vein and hope that the cells will migrate to sites of injury and remain at those sites long enough to participate in the repair process. While some cells certainly do migrate to injury sites, the actual percentage is very small and those that arrive at the site do not remain to engraft with the host tissue," explained Boyan.
This limited effect may be the result of the injection process, according to Boyan, so researchers in the center are developing ways to protect the cells from damaging forces they might encounter when inserted into the body.
"Studies in our laboratory have shown that when stem cells are encapsulated in microbeads, they can be injected by needle without loss of cell viability and they remain at the injury site for at least two months," said Boyan.
Protecting the cells during insertion is just the first step toward improved tissue repair. The researchers must also examine whether the stem cells will turn into cells typical of the implanted tissue and if they produce or should be paired with molecules that can enhance the healing of the implanted tissues.
Center researchers are also investigating whether bone marrow-derived stem cells can be used in the body to heal large defects in bone and cartilage if they are inserted in fiber mesh scaffolds and silk sponges during a surgical procedure.
Additional projects in the center include assessing tissue viability, preventing the growth of bone in the soft tissues of the body and improving pre-hospital care of orthopedic injuries. Since effective treatment of traumatic injuries is an important goal for the general public as well as the military population, the researchers also hope to adapt their technologies for use in hospitals.
Other researchers in the center include Ravi Bellamkonda, a professor in the Coulter Department; Andres Garcia, the Woodruff Faculty Fellow in the Woodruff School of Mechanical Engineering; Robert Taylor, a professor in the Coulter Department and Emory's Division of Cardiology; Zvi Schwartz, a visiting professor in the Coulter Department; and U.S. Army surgical medicine consultants Michael Yaszemski and David Cohen.
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Writer: Abby Vogel