Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society
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Comparative Study
A silicone-based controlled-release device for accelerated proteolytic debridement of wounds.
A new device for rapid enzymatic debridement of cutaneous wounds has been developed using a controlled-release, silicone-based, dried emulsion. A dehydrated serine protease of the subtilisin family, previously untested for wound debridement, was incorporated into the emulsion. This device exhibited excellent storage stability. ⋯ The device maintains a moist wound environment that allows the enzyme to achieve nearly complete digestion of the hardened eschar of full-thickness burns in a porcine model after an exposure period of 24 hours. Debridement was faster than in untreated wounds or wounds treated with a currently available enzyme ointment. Following rapid enzymatic debridement, healing appeared to progress normally, with no histological evidence of damage to adjacent healthy tissue.
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Large complicated leg ulcers, not responsive to standard therapy, after surgical debridement and under parenteral specific antibiosis, must be occlusively covered to improve wound healing. In 10 diabetic patients with deep (Wagner degree 3), large, and Staphylococcus aureus (n=7) or Pseudomonas aeruginosa (n=5)-infected leg (n=1), or foot (n=9) ulcers, we have applied, as a coverage, meshes of in vitro expanded autologous fibroblasts. ⋯ One patient, previously submitted to a bypass vascular procedure, died of acute myocardial infarction 16 weeks after the first fibroblast autograft application and with a healing wound evenly filled with granulation tissue. In our opinion, the application of autologous in vitro expanded fibroblasts is a satisfactory therapeutic option to treat large leg ulcers and is particularly indicated in patients with chronic diseases such as diabetes or autoimmune diseases on steroid treatment.
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Comparative Study
A comparative study of the cytotoxicity of silver-based dressings in monolayer cell, tissue explant, and animal models.
Over the past decade, a variety of advanced silver-based dressings have been developed. There are considerable variations in the structure, composition, and silver content of these new preparations. In the present study, we examined five commercially available silver-based dressings (Acticoat, Aquacel Ag, Contreet Foam, PolyMem Silver, Urgotul SSD). ⋯ In the mouse excisional wound model, Acticoat and Contreet Foam indicated a strong inhibition of wound reepithelialization on the postwounding-day 7. These findings may, in part, explain the clinical observations of delayed wound healing or inhibition of wound epithelialization after the use of certain topical silver dressings. Caution should be exercised in using silver-based dressings in clean superficial wounds such as donor sites and superficial burns and also when cultured cells are being applied to wounds.
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Fibroblasts and myofibroblasts migrating to sites of tissue repair after injury may not only be locally recruited but could also be recruited from the bone marrow. However, the characteristics and functional roles, if any, of these cells in wound healing are poorly understood. Here, we show unequivocally that bone marrow-derived fibroblasts do contribute to deep dermal burn wound healing. ⋯ PKH-positive cells were not found at day 7, but by day 10, they were easily detected mainly in the upper dermis close beneath the regenerating epidermis. These PKH-positive cells still stained for alpha-SMA and prolyl 4-hydroxylase, but not RM4. Thus, it is suggested that myofibroblasts originating in the bone marrow contribute not only to promotion of granulation but also enhancement of dermal-epidermal interaction after thermal injury.
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High levels of tumor necrosis factor-alpha (TNF-alpha), a pro-inflammatory cytokine, are present in the wound fluid of chronic nonhealing wounds. This leads to increased inflammation, cytokine expression, and ultimately results in impaired wound healing and tissue destruction. Etanercept is a recombinant fusion protein that consists of the soluble TNF receptor (p75) linked to the Fc portion of human IgG1. ⋯ The effect of Etanercept on TNF-alpha activity was evaluated using both a TNF-alpha bioassay and an enzyme-linked immunoassay. Etanercept was found to reduce the cytotoxic effect of chronic wound fluid on L929 fibroblasts by approximately 30% and neutralized TNF-alpha binding in the enzyme-linked immunoassay by up to 80%. Direct application of Etanercept to chronic wounds may therefore reduce the inflammatory activity of TNF-alpha, which could reduce the chronicity of venous leg ulcers and thus aid in the healing of these wounds.