A Head-to-Head Comparison of Topical Collagen Powder to Primary Closure for Acute Full-Thickness Punch Biopsy-Induced Human Wounds: An Internally Controlled Pilot Study
July 2019 | Volume 18 | Issue 7 | Original Article | 667 | Copyright © July 2019
Azam Qureshi BA,a Emily Murphy BS,b,c Rose Milando BA,b Monica Rengifo-Pardo MD,b Courtney Clayton,b Adam Friedman MD FAADb,c
aUniversity of Maryland School of Medicine, Baltimore, MD
BGeorge Washington University School of Medicine and Health Sciences, Washington, DC
cGeorgetown University School of Medicine, Washington, DC
dGeorge Washington Medical Faculty Associates, Washington, DC
Background: Collagen-based products have been implemented in wound healing due to collagen’s hemostatic properties, low antigenicity, and poor culture ability.
Objective: To compare the rate and quality of full-thickness wound healing for topical collagen powder and primary closure.
Methods: Eight volunteers received one 4 mm punch biopsy on each thigh. One wound was managed with primary closure while the other received daily collagen powder. Wounds were biopsied at four weeks for histopathological analysis. Subjects rated itch, pain, and treatment preferences at weeks 1, 2, 4, 6, and 12.
Results: Six out of eight collagen-treated wounds were completely healed 4 weeks after initial wounding. Histologic analysis of the wounds revealed epidermal re-epithelization in both groups. More organized granulation tissue was noted in collagen-treated wounds and confirmed using Masson trichrome and CD31 staining for collagen and neoangiogenesis, respectively. Subjects reported similar itch and pain metrics between wounds. Both subjects and blinded dermatologists preferred the early cosmetic appearance of collagen-treated wounds over primarily closed wounds.
Limitations: Small sample size, absence of negative control.
Conclusion: These data suggest that collagen powder is non-inferior to primary closure at the macro- and microscopic levels, while possibly leading to superior early cosmetic outcomes and accelerated histologic wound maturation.
Ethics/Clinical Trials Registration: Study was approved by the George Washington University Institutional Review Board (IRB protocol #121745). ClinicalTrials.gov: NCT03481907.
J Drugs Dermatol. 2019;18(7):667-673.
Collagen, an essential component of the extracellular matrix (ECM), is a triple helical structure composed of three polypeptide chains.1–3 During normal wound healing, collagen acts as a scaffold for cellular ingrowth and organized deposition of new collagen.2,4 Proteases degrade native collagen, releasing polypeptide fragments that act as chemotactic molecules to recruit inflammatory mediators, promote keratinocyte migration, and stimulate the proliferation of fibroblasts and subsequent collagen deposition.2,4,5 Collagen-based dressings and fractionated collagen powders have been developed for wound therapy as they are thought to replace degraded collagen by bypassing enzymatic breakdown.2,4,6 Furthermore, powdered collagen supports ECM production and acts as a signaling molecule, recruiting inflammatory cells, fibroblasts, and keratinocytes.7,8 Collagen has low antigenicity and can be left in wounds without causing irritation or enhancing bacterial growth.9,10 Additionally, collagen promotes thrombosis and hemostasis and has hydrophilic properties useful for absorbing fluid in exuding wounds.11,12 These factors make collagen an ideal wound therapy agent.
Punch biopsies are frequently performed for diagnostic purposes and are often closed primarily with non-absorbable sutures, but may also be left to heal by secondary intention. In a recent survey distributed by the present authors to providers on the Orlando Dermatology Aesthetic and Clinical Conference emailing list, 877 (29.6% response rate) providers completed a survey in which only 5.13% of respondents indicated that they leave a 4mm punch biopsy wound open to heal by secondary intention (data not published). Most respondents were MD/DOs (98.6%), with many being in practice for more than 10 years (38.4%, data not published). While clearly commonly used, it is important