The remarkable natural process of wound healing in bone and soft tissues is not the result of a single event or stimulus but appears to be a "cascade" of events whose flow may be altered at several points along the way by chemical and physical factors.
Over the past several years, researchers have shown the positive effects of growth factors on healing soft tissues. Less is known, however, about the effect of growth factors in stimulating growth in bones, especially in the bones of elderly individuals or those with debilitating diseases such as diabetes.
Dr. Robert I. Howes, associate professor of anatomical sciences at the University of Oklahoma Health Sciences Center, hopes the knowledge gained during a three-year, $61,000 project sponsored by the Oklahoma Center for the Advancement of Science and Technology will provide such information.
"It's important to try to improve healing of fractures and hard tissue wounds in older individuals as well as in those who have some sort of debilitating disease which delays healing," Howes said. "Newly discovered growth factors and their mode of delivery may improve this healing." Howes is concentrating his studies on rat models using two growth factors, platelet-derived growth factor (PDGF) and transforming growth factor, beta (TGFB), which may affect bone growth.
"PDGF is sometimes called the would healing hormone and is manufactured in many cells, including the body's blood platelet, whose contents are released upon wounding," Howes said. "It stimulates the division and migration of osteoprogenetor cells (cells that eventually will form new bone and cartilage) into the injured area to begin the process of healing.
"Stimulation of wound healing with additional growth factors in young animals has very little effect because the growing animal already is producing an excess amount, but there definitely is a difference in older animals in which the bone healing process is slower. …