Exploring The Potential Of Growth Factors In Chronic Wounds
Do growth factors improve the rate of wound healing? When is it appropriate to use them on chronic wounds? Is the cost of growth factor modalities worth the results? Our expert panelists answer these key questions, share their experiences and ponder the future of these modalities with their discussion about the efficacy of growth factors in chronic wound care. Without further delay, here is what they had to say …
Q: When, why and how do you utilize growth factors in the treatment of foot and ankle wounds?
A: Wound bed preparation is the first step in approaching all wounds, notes Thomas E. Serena, MD, FACS. This includes primary and serial debridement, ensuring proper moisture balance and reducing bacterial burden. Jason Weber, DPM, concurs, emphasizing that one may employ growth factors in conjunction with proper wound care, including frequent debridement. Quoting a 1996 study by Steed, Dr. Weber says “wound debridement is a vital adjunct in the care of … diabetic foot ulcers.”
Barry Rosenblum, DPM, and Susan G. Woods, MD, say they consider using growth factors in non-infected foot and ankle wounds when they have failed to heal in a reasonable period of time and other variables (such as arterial blood supply, debridement and offloading) are at optimal levels. Growth factors are an important part of the wound healing phases and Dr. Woods notes platelet-derived growth factor (PDGF) is one of the earliest growth factors to be identified in the process by researchers.
“Growth factors help stimulate fibroblasts to make collagen, angiogenesis and chemotaxis, which is especially important in the proliferative phase of wound healing,” explains Dr. Woods.
PDGF, a topical gel (Regranex, Johnson and Johnson) which one applies directly to the wound, is the only growth factor approved by the FDA for diabetic ulcers, notes Dr. Woods. She adds that studies have found the combination of ulcer debridement and PDGF has a synergistic effect on healing.
Recently, Lawrence G. Karlock, DPM, says he has been utilizing topical growth factors “in an earlier period” than he traditionally used them in the last decade. While he notes an initial reluctance to use this modality due to cost concerns, Dr. Karlock says he has been “pleasantly surprised” that these topical growth factors can actually “kickstart a chronic wound into epithelialization.” If a patient presents with an uninfected granulating wound, Dr. Serena says he may use PDGF on the first visit. Dr. Karlock does not employ topical growth factors initially for any acute wounds. However, Dr. Serena has found that in treating acute wounds in healthy patients, PDGF worked best when applied every other day. He cautions against extrapolating this timetable into chronic wound care.
Q: Are there any new theories or science about the role of PDGF in wound care? Specifically, how long does it take for PDGF to work in the wound?
A: In theory, PDGF should work on all chronic wounds, posits Dr. Woods. However, she notes that science has shown the success of PDGF in the diabetic wound is due to the “persistence of biological activity of this peptide in the wound microenvironment.
“The microenvironment of these chronic wounds can be very hostile to proteins and breakdown of PDGF by proteases is likely,” explains Dr. Woods. “Therefore, discovering an optimal delivery system is key to the success of PDGF.”
When it comes to healing chronic foot and ankle wounds, Dr. Rosenblum says he also considers bioengineered skin as “a delivery system of a variety of growth factors as opposed to applying a single growth factor.” In his experience, Dr. Rosenblum has found that if PDGF is effective, one will see results within 12 to 20 weeks. He points out this is the same healing time one would see with living skin equivalents or bioengineered skin.