Human amniotic fluid derived cells can competently substitute dermal fibroblasts in a tissue-engineered dermo-epidermal skin analog

<p>Human amniotic fluid comprises cells with high differentiation capacity, thus representing a potential cell source for skin tissue engineering. In this experimental study, we investigated the ability of human amniotic fluid derived cells to substitute dermal fibroblasts and support epidermis formation and stratification in a humanized animal model.</p><p>Dermo-epidermal skin grafts with either amniocytes or with fibroblasts in the dermis were compared in a rat model. Full-thickness skin wounds on the back of immuno-incompetent rats were covered with skin grafts with (1) amniocytes in the dermis, (2) fibroblasts in the dermis, or, (3) acellular dermis. Grafts were excised 7 and 21 days post transplantation. Histology and immunofluorescence were performed to investigate epidermis formation, stratification, and expression of established skin markers.</p><p>The epidermis of skin grafts engineered with amniocytes showed near-normal anatomy, a continuous basal lamina, and a stratum corneum. Expression patterns for keratin 15, keratin 16, and Ki67 were similar to grafts with fibroblasts; keratin 1 expression was not yet fully established in all suprabasal cell layers, expression of keratin 19 was increased and not only restricted to the basal cell layer as seen in grafts with fibroblasts. In grafts with acellular dermis, keratinocytes did not survive.</p><p>Dermo-epidermal skin grafts with amniocytes show near-normal physiological behavior suggesting that amniocytes substitute fibroblast function to support the essential cross-talk between mesenchyme and epithelia needed for epidermal stratification. This novel finding has considerable implications regarding tissue engineering.</p>

Cellular- and Acellular-Based Therapies: Skin Substitutes and Matrices

Recalcitrant wounds pose a challenge to the dermatologist. In recent years, many skin substitutes have been developed and are broadly classified as either acellular or cellular. These skin substitutes are to be used in concert with standard of care to provide the stalled wound with a scaffold and key elements such as cytokines, growth factors, and extracellular matrix substances. Skin substitutes help initiate and accelerate wound healing through granulation, cell migration, re-vascularization, and re-epithelialization. Wounds of varying etiologies have been shown to benefit from the multitude of acellular and cellular skin substitutes that are available. This chapter provides clinically relevant background and practical guidance about skin substitutes to allow dermatologists to effectively incorporate these powerful tools into their wound healing armamentarium