The expression pattern of cytokeratin 6a in epithelial cells of different origin in dermo-epidermal skin substitutes in vivo

Keratinocytes are the predominant cell type of skin epidermis. Through the programmed process of differentiation, they form a cornified envelope that provides a physical protective barrier against harmful external environment. Keratins are major structural proteins of keratinocytes that together with actin filaments and microtubules form the cytoskeleton of these cells. In this study, we examined the expression pattern and distribution of cytokeratin 6a (CK6a) in healthy human skin samples of different body locations, in fetal and scar skin samples, as well as in dermo-epidermal skin substitutes (DESSs). We observed that CK6a expression is significantly upregulated in fetal skin and scar tissue as well as in skin grafts after short-term transplantation. Importantly, the abundance of CK6a corresponds directly to the expression pattern of wound healing marker CK16. We postulate that CK6a is a useful marker to accurately evaluate the homeostatic state of DESSs. Cytokeratins (CKs) are the major components of the epithelial cytoskeleton responsible for maintaining the structural stability and integrity of keratinocytes. CK6a has been identified as a marker for activated and hyperproliferative keratinocytes. However, still little is known about the exact distribution of this marker is human skin samples of different body locations as well as in tissue-engineered dermo-epidermal skin substitutes (DESSs). In this study, we developed DESSs containing keratinocytes and (KC) fibroblasts (FB) derived from different body locations. Subsequently, we investigated whether the KC in DESSs express CK6a after in vivo transplantation onto immune-comprised rats. We postulate that CK6a is a useful marker to evaluate the maturation status and homeostatic state of tissue engineered skin grafts.image