Genetically Engineered Protein Speeds Wound Healing
Minute quantities of a genetically engineered protein can accelerate the healing of human wounds, according to a study of 12 patients reported in today’s New England Journal of Medicine.
The preliminary findings by a team of researchers led by Dr. Gregory L. Brown of the University of Louisville may lead to improved treatments for patients with severe burns and chronic wounds, such as bedsores and foot ulcers.
The report, the first of its kind in humans, “is a historical event,” said Dr. Thomas K. Hunt of UC San Francisco, the co-author of an editorial published in the medical journal along with the study.
“Wound healing has been one of the last frontiers for medicine to try to influence,” Hunt said in an interview. “These people have not (hastened wound healing) by a huge margin, but they have done it.”
Faster Healing
The researchers found that areas of wounded skin treated with the protein healed an average of 1 1/2 days faster than comparable areas that were not treated with the substance. Previously, they and others had obtained similar results in animal studies.
But the researchers have yet to demonstrate that the use of the experimental growth factor has important clinical effects in humans, such as the ability to prevent wound infections, decrease pain or shorten hospital stays. Larger studies seeking to show such benefits are in progress, Brown said.
The protein is known as human epidermal growth factor (epidermis is a medical term for the outer layers of the skin). It is one of a group of proteins that play a key role in regulating cell and organ development in animals and humans. In 1986, Stanley Cohen, a biochemist, and Rita Levi-Montalcini, a neurobiologist, were awarded the Nobel Prize in medicine for the discovery of growth factors.
Genetic Engineering
Epidermal growth factor is normally produced by the body. It is already present in many injured areas of skin. Scientists have reasoned that they might hasten the healing process by applying creams containing additional growth factor to wounds and burns. The protein is produced in the laboratory using genetic engineering techniques.
The new study involved 12 patients who required skin grafts for various reasons, primarily for treatment of burns. To perform such grafts, surgeons often cover areas where skin had been lost with a partial thickness of healthy skin taken from “donor sites” on the patient’s own body. The removal of the healthy skin, in effect, creates a wound.
For each patient in the study, two paired donor sites were selected. After the skin for grafting was removed, one donor site was treated with a cream commonly used to prevent infections. The other site was treated with a preparation of the cream that contained epidermal growth factor. Neither the researchers nor the patients knew which donor site received the growth factor treatments.
The creams were applied every 12 hours.
The researchers found that treatment with epidermal growth factor “significantly decreased the average length of time” to achieve total wound healing by about 1 1/2 days. Accelerated healing was seen in all patients; typically, the wounds took one to two weeks to heal entirely.
After a minimum of one year of follow-up, the researchers said there had been no complications, such as abnormal scars or early evidence of skin tumors.
Brown said the study was important because it showed “efficacy in man,” not because physicians would necessarily use the growth factor exactly as it was used in the study. The growth factor might prove most valuable for “problematic, non-healing wounds,” he said. These include bedsores, diabetic skin ulcers and venous skin ulcers of the lower legs, as well as extensive burns, where skin grafts must be repeatedly harvested from non-burned areas of the body. Patients with extensive burns often spend months in the hospital.
In their New England Journal editorial, Hunt and Dr. Frederick B. La Van, also of UCSF, sounded a cautionary note. “Critics will no doubt note that the practical results of this study are trivial,” they wrote. The editorial pointed out that other researchers had used similar experiments to demonstrate “equivalent accelerations” in the rate of wound healing with the use of oxygen, electromagnetic waves, and Preparation H, an over-the-counter hemorrhoidal remedy that contains a “live yeast cell derivative.”
But Hunt and La Van said that the new study advanced upon these earlier efforts.
They added: “The annual market for products used in the care of wounds in this country is more than $1 billion, and a successful growth factor-based product would be expected to capture a substantial share of the market.”
The epidermal growth factor research was conducted at the University of Louisville, Vanderbilt University in Nashville and Emory University in Atlanta. The growth factor was manufactured by Chiron Corp., of Emeryville, Calif., one of a number of biotechnology firms that are seeking to develop growth factor-based medications.
