Recent advances in tissue engineering hold great promise for alleviating the current shortage of tissues and organs available for transplantation. However, engineered skin tissue produced with primary human keratinocytes is slow to vascularize following engraftment, resulting in tissue ischemia and a low frequency of graft take. These limitations may be overcome by genetically modifying the tissue such that it produces factors that are known to promote vascularization and angiogenesis. The ultimate goal of these studies is to develop cultured skin tissue that exhibits accelerated vascularization and improved wound healing following engraftment. During Phase I, it was demonstrated that human NIKS TM keratinocytes can be stably modified to express elevated levels of angiogenic factors from non-viral vectors. This Phase II SBIR proposal is designed to expand upon progress made during Phase I by determining whether cultured skin tissue that expresses elevated levels of angiogenic growth factors will exhibit accelerated vascularization in an animal model of wound healing. The expression profiles and growth characteristics of multiple independent stably-transfected keratinocyte clones will be characterized to identify clones that express different levels of the angiogenic factors. Skin tissue prepared from these NIKS TM cells will be grafted onto mice and monitored over time to quantify the effect of angiogenic factor expression on wound healing and vascularization. Successful completion of these studies will position this technology for further pre-clinical assessment and ultimate evaluation in human clinical trials.
