Interferons (IFNs) belong to the family of cytokines are widely used to treat keloids owing to their ability to increase collagenase activity thereby reducing the production of collagen and other extracellular matrix (ECM). Intralesional injection of IFN-α -2b increases the collagenase level by inhibiting the secretion of metalloproteinases, an inhibitor of collagenase. Moreover, the anti-fibrotic activity of IFNs, interfere with fibroblast mediated collagen synthesis. On the other hand, combinatorial therapy has been preferred recently along with IFN due to its side effects observed in various clinical trials conducted only with IFN. Triamcinolone acetonide (TAC) and CO 2 lasers along with IFNs are found to be the potential therapy for the treatment of scars and keloids. In this chapter, IFN mediated therapy for the treatment of scars and keloids, its benefits and limitations and the advantages of combinatorial therapy with the appropriate literature support are discussed.

Tissue-engineered skin is a significant advance in the field of wound healing and was developed due to limitations associated with the use of autografts. These limitations include the creation of a donor site which is at risk of developing pain, scarring, infection and/or slow healing. A number of products are commercially available and many others are in development. Cultured epidermal autografts can provide permanent coverage of large area from a skin biopsy. However, 3 weeks are needed for graft cultivation. Cultured epidermal allografts are available immediately and no biopsy is necessary. They can be cryopreserved and banked, but are not currently commercially available. A nonliving allogeneic acellular dermal matrix with intact basement membrane complex (Alloderm) is immunologically inert. It prepares the wound bed for grafting allowing improved cultured allograft 'take' and provides an intact basement membrane. A nonliving extracellular matrix of collagen and chondroitin-6-sulfate with silicone backing (Integra) serves to generate neodermis. A collagen and glycosaminoglycan dermal matrix inoculated with autologous fibroblasts and keratinocytes has been investigated but is not commercially available. It requires 3 to 4 weeks for cultivation. Dermagraft consists of living allogeneic dermal fibroblasts grown on degradable scaffold. It has good resistance to tearing. An extracellular matrix generated by allogeneic human dermal fibroblasts (TransCyte) serves as a matrix for neodermis generation. Apligraf is a living allogeneic bilayered construct containing keratinocytes, fibroblasts and bovine type I collagen. It can be used on an outpatient basis and avoids the need for a donor site wound. Another living skin equivalent, composite cultured skin (OrCel), consists of allogeneic fibroblasts and keratinocytes seeded on opposite sides of bilayered matrix of bovine collagen. There are limited clinical data available for this product, but large clinical trials are ongoing. Limited data are also available for 2 types of dressing material derived from pigs: porcine small intestinal submucosa acellular collagen matrix (Oasis) and an acellular xenogeneic collagen matrix (E-Z-Derm). Both products have a long shelf life. Other novel skin substitutes are being investigated. The potential risks and benefits of using tissue-engineered skin need to be further evaluated in clinical trials but it is obvious that they offer a new option for the treatment of wounds.

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A scar from an acute surgical wound becomes softer, more elastic, dryer, less erythematous, and less pigmented as it ages. In contrast, chronic wound scars become harder as they age. These different properties of healed acute wounds and healed chronic wounds may be a result of the different healing processes in each wound type.