Prevention of Contracture in Full Thickness Wounds Using Photochemical Tissue Passivation (PTP)
*Jane M. Tsui, *Rachel L. Goldstein, *Gem Runyan, *Michael C. McCormack, *Robert W. Redmond, *Mark A. Randolph, William G. Austen, Jr.
Massachusetts General Hospital, Boston, MA
Objective: Wound contracture is a debilitating complication resulting from excessive myofibroblast activity during wound healing. Currently, no treatment to prevent contracture exists. Photochemical Tissue Passivation(PTP) occurs when tissue is coated with photosensitive dye and exposed to visible light. PTP has been shown in other animal models to decrease fibroblast-mediated collagen contraction, decrease myofibroblast activity and strengthen tissue. We hypothesize that PTP treatment to full-thickness wounds will significantly decrease wound contracture morbidities by strengthening the wound bed and limiting the myofibroblast response.
Design: Randomized control trial.
Setting: Trained medical professionals can use this treatment in any setting.
Patients: Thirty-two C57BL/6 mice were randomized to the untreated control group (n=16) or the PTP treatment group (n=16).
Interventions: 1x1 cm full-thickness excisional wounds were created on the dorsum of all mice. PTP wound beds were painted with photosensitive dye and exposed to visible light at a fluence of 60J/cm2.
Main Outcome Measures: Wounds were serially photographed for 6-weeks to measure percent contracture. At 7, 14, 21, and 42 days post-operatively, animals were euthanized and wound skin was harvested for histological review by a dermatopathologist.
Results: Treated wounds contracted significantly less than controls. At 7 days, control groups showed nearly 20% more contracture (67.1±17.1% vs 80.3±8.5%; p=0.014), and by 14 days, over 80% more (27.8±8.6% vs 50.3±11.9%, p<0.05). At 21 days, PTP wounds were 1.05-fold less contracted (p<0.05). At 42 days, control wounds contracted to 13.6±5.6% and PTP wounds to 35.2±2.9% (p=0.003). Histologically, PTP wounds had earlier and increased dermal collagen development and ingrowth, neovascularization, and development of skin appendages compared to controls.
Conclusions: PTP significantly limits contracture in full-thickness excisional wounds, and may accelerate and improve wound healing.