RESUMEN
Current evidence supports the use of excision to remove eschar from deep dermal and full-thickness burns. However, the role of excision of mid-dermal burns remains unclear. This study aimed to develop a porcine model that could produce reproducible middermal thermal burns that undergo tangential excision; and investigate the effects of immediate tangential excision (30 minutes postburn) on healing and scarring. An aluminum bar preheated in hot water (70°C) was applied for 20 or 30 s to produce a total of sixteen mid-dermal burns per pig on each of six pigs. Thirty minutes after burn creation, half of the burns were tangentially excised. Four partial- thickness wounds per pig were created as controls. Depth of burn injury (1 and 24 h), reepithelialization (7 and 10 d) and scar depth (28 d) were assessed microscopically. Total scar surface area was grossly evaluated on day 28. Exposure of porcine skin to a preheated aluminum bar at 70 °C for 20 or 30 sec resulted in reproducible mid-dermal burns, where immediate excision enhanced complete wound closure as judged by complete re-epithelialization, but did not reduce initial depth of injury, scar contraction and scar depth. Immediate surgical intervention is sufficient to enhance wound closure, but not to mitigate mid-dermal burn scar formation. This work provides a suitable animal model to evaluate novel therapies that may be used to inhibit burn progression, accelerate wound closure and decrease scarring, especially those therapies unable to penetrate burn eschar.
Les données actuelles des connaissances sont en faveur de l'excision des brûlures des 2ème degré profond et 3ème degré. L'intérêt de l'excision des brûlures intermédiaires reste mal précisé. Cette étude se penche sur un modèle porcin destiné à la réalisation de brûlures intermédiaires reproductibles et à l'évaluation de l'effet l'excision ultra précoce (30 mn après la brûlure) sur l'épidermisation et la cicatrisation de ces brûlures. Six porcs ont subi chacun un total de 16 brûlures intermédiaires infligées au moyen d'une barre d'aluminium chauffée à 70°C et appliquée pendant 20 à 30 s. La moitié des zones brûlées étaient excisées à la trentième minute. Quatre brûlures superficielles servaient de contrôle. La profondeur de la brûlure (à h1 et h24), la réépithélialisation (à J7 et J10) et l'épaisseur de la cicatrice (à J28), étaient étudiées microscopiquement. La surface cicatricielle totale était évaluée à J28. L'exposition pendant 20 à 30s de la peau d'un porc à de l'aluminium préalablement chauffé à 70°C entraîne une brûlure intermédiaire reproductible. L'excision immédiate en favorise la guérison lorsqu'elle est jugée sur la réépithélialisation mais n'en réduit ni la profondeur, ni la rétraction cicatricielle, pas plus que l'épaisseur de la cicatrice. L'excision immédiate favorise la fermeture de la plaie mais pas son évolution vers des séquelles. Ce travail permet de décrire un modèle animal fiable dans le but d'évaluer de nouvelles thérapeutiques destinées à limiter le progression des lésions, accélérer la fermeture et diminuer la survenues de séquelles, en particulier celles incapables de pénétrer dans une lésion constituée.
RESUMEN
Currently, autografts are the best treatment to any substantial cutaneous injury, and their success is well known as a burn therapy. However, autografts have been less successful in the treatment of chronic ulcers, and are usually a last-resort therapy because of infection at the injured site, high surgical expense, additional morbidity and engraftment failure. In addition, patients with burns covering more than 50% of their skin have limited donor sites for autograft harvest. Therefore, there is a great need for a cost-effective, user-friendly, tissue-engineered construct (TEC) that can provide successful treatments to both acute and chronic wounds in a wider repertoire of patients, including diabetics and the elderly. One approach to the challenge is to create a substitute for skin in vitro that can integrate into the engraftment site in vivo. An alternative is to engineer a biocompatible, resorbable matrix that can recruit the proper, native tissue cells to the injured site and induce them to heal the wound without scarring. This chapter reviews the 3 essential components of cutaneous wound healing, that is, cells, extracellular matrix molecules and bioactive molecules, that must be considered for designing TECs to potentially enhance the healing process. In nature, a 'dynamic reciprocity' exists amongst cells and extracellular matrix that is mediated by bioactive molecules at the site of injury. Thus, it is important to examine the interplay of all 3 components when engineering a TEC. This chapter also includes examples of commercially available products to highlight how researchers have already begun to find success in tissue engineering.
