Researchers have received a grant from the U.S. Department of Defense to study ways in which nicotine from cigarette smoke may interact with stem cells to slow the healing of bone injuries. Smoking has been shown to delay skeletal healing by as much as 60 percent following fractures. Slower healing means a greater chance of re-injury and can lead to chronic pain and disability. The obvious solution is for smokers to quit when they get hurt, but studies show that just 15 percent can. The military is interested in the issue because about 34 percent of military personnel smoke, compared to 25 percent in the general population, according to the Air Force Medical Support Agency. Long-term health concerns aside, military experts say smoking reduces soldiers’ readiness to fight by impairing night vision, weakening the immune system and lengthening healing time. The problem is especially poignant now because more than 14,000 soldiers have been injured in Iraq since 2003, with about 65 percent of the injuries including orthopedic damage to extremities. One goal of the research then is to determine, based on biochemical evidence, the window of time during which healing has the greatest chance of being delayed by cigarette smoke. Smokers could then be advised to quit for a specific time period to afford them their best chance of healing. Beyond the time window, researchers hope a better understanding of the mechanisms involved will lead to treatments that speed healing in persistent smokers and in all patients with bone injuries. “Smoking reduces the rate at which the two sides of a fracture come together,” said Michael Zuscik, Ph.D., assistant professor in the Department of Orthopaedics at the University of Rochester Medical Center, recipient of the $1.4 million DOD grant. “We believe this new research will establish for the first time the mechanisms by which nicotine interferes with the healing process, and identify ways to prevent it.” Zuscik’s work hinges on the theory that nicotine prevents stem cells from maturing into replacement bone.
