Skin, which is the most extensive organ in the human body, performs multiple vital functions. Wounds to this organ, whether chronic or acute, are a serious threat because they leave the body open to infection. That’s why burns are a major cause of infection-associated deaths and why early replacement of burned tissues is so critically important. There is an urgent need to engineer skin substitutes for patients with extensive burns who do not have enough skin available for harvesting as grafts to close wounds. However, relatively little is known about how to establish a large-scale production of skin substitutes and how to control the healing process when such material is used. Bone marrow-derived stem cells may be a potential source for the preparation of skin substitutes due to their capacity to be reprogrammed to produce a variety of cell types. Abelardo Medina is studying whether bone marrow-derived stem cells can be used in this fashion both to close wounds and to improve wound healing. Findings from his research may also lead to a better understanding of the healing process and the treatment of chronic non-healing ulcers that develop in elderly people, diabetic and immuno-compromised patients. It also may contribute to a better understanding of the processes associated with over-healing wounds such as those that result in thick burn scars.