Tissue-Engineered Products for Skin Regenerative Medicine

In a general wound healing process, foreign bodies and tissue detritus have to be broken down and then a new tissue is produced. However, the new tissue formation sometimes fails to proceed under the impaired conditions such as burn injury and intractable skin ulcer. A major obstruction to wound healing is infection. Another obstruction to wound healing is deficiency of growth factors. The endogenous levels of growth factors are reduced in some chronic wounds. To improve these wound conditions, researchers have been trying to create several types of artificial skins. The tissue-engineered products include three prime constituents, i.e., cells, growth factors, and materials. In this review, the practical design of tissue-engineered products for skin regenerative medicine is introduced. The first design makes it possible to release silver sulfadiazine (AgSD) from a wound dressing. The second design makes it possible to release Epidermal Growth Factor (EGF) from a wound dressing or a skin care product composed of hyaluronic acid spongy sheet containing bioactive ingredients. The third design makes it possible to release several types of growth factors from allogeneic fibroblasts within cultured dermal substitute. This tissue-engineered product is prepared by seeding allogeneic fibroblasts into a collagen and hyaluronic acid spongy sheet. Although allogeneic cells are rejected gradually in immune system, they are able to release some types of growth factors, thereby regenerating a damaged tissue. The clinical study demonstrates that these tissue-engineered products are promising for the treatment of burn injury and intractable skin ulcer.