January 31, 2002
Understanding burn scars: Surgeon Nicole Gibran tries to learn how hypertrophic scars might be reduced or prevented
| Pamela Wyngate |
| HS News & Community Relations |
After a suffering a severe burn, some patients develop hypertrophic scars—a distinct and excessive growth of tissue with increased numbers of blood vessels and multiple nerves. Researchers interested in wound healing want to know why some people develop these scars and others do not.
“We treat about 500 burn patients a year here at Harborview,” says Dr. Nicole Gibran, associate professor of surgery. “About 40 percent of them develop a serious problem with scar formation. These scars are ugly. They’re raised. They’re itchy. If they’re on the face, others’ eyes are just drawn to them. They’re lumpy, bumpy—this is a major source of misery for our patients.”
It’s unclear why darker-skinned people and children are more likely to develop hypertrophic scars. These scars also rarely occur on the scalp and forehead. They do, however, happen with great frequency in the area over the breastbone. Researchers at the UW believe this may have something to do with the architecture of skin around the follicles in these areas.
While Gibran is enthusiastic about any and all work in scar formation, she has focused her studies on the role of nerves in wound repair.
“People have studied the histology and examined hypertrophic scar samples under a microscope; there is an increased number of nerves in the tissue itself,” says Gibran. “The nervous system, besides causing pain, has the ability to contribute to the inflammatory response, so nerves produce mediators that promote inflammation at the wound site.”
Mediators are proteins, such as cytokines, that are released at the site of a burn. These proteins participate in a kind of cross talk between the blood vessels and the nerves.
“The bulk of my research is to try and understand the process by which the proteins that the nerves produce may influence inflammation,” says Gibran. “Taking an anti-inflammatory drug does not reliably get rid of the itching. My interest in that would be far more than just solving the itching—people go crazy from the itching—but beyond that I’d like to prevent the scar from forming in the first place.”
At present, immediate skin grafts are usually a burn patient’s best option. There is not reliable prevention or therapy for hypertrophic scar formation.
One of the greatest challenges to studying hypertrophic scars is the lack of an animal model. Most animals simply do not develop hypertrophic scars. Horses produce something called “proud flesh” that may be similar to hypertrophic scarring, but this is an anomaly in the animal world.
Gibran’s group hypothesizes that hypertrophic scars are essentially the opposite of diabetic neuropathy in humans. Perhaps the deficient wound repair associated with diabetic neuropathy is the result of a decrease in the number of nerves.
“Since there are models for diabetic wound healing,” explains Gibran, “I’ve adopted that as a means to study the roles of nerves in wound healing. Ultimately as a researcher I would like to be able to find an etiology for these scars. We don’t yet understand really why it happens.”
Gibran presents “Making Sense of Wound Repair” at the Science in Medicine lecture, Thursday, Feb. 7, at noon in A-420 Hogness Auditorium, Health Sciences Center. Everyone is welcome.
Gibran received a M.D. from Boston University in 1985. From 1985 to 1990 she completed a residency in surgery at the Boston University Department of Surgery. Gibran came to the UW in 1990. She completed a one-year fellowship at the UW Burn Center and a two-year NIH Trauma Fellowship in the Department of Surgery from 1991 to 1993. She followed that with a one-year fellowship from the Northwest Burn Foundation. Gibran became acting instructor of surgery in 1990, assistant professor in 1994 and associate professor in 1999. Gibran has been an attending surgeon at the UW Medical Center and Harborview since 1994.
