Increasing skin blood flow is critical for humans to appropriately regulate internal temperature during exercise and/or hyperthermic exposure. Wounds, such as burns, can damage skin, requiring removal of damaged tissue and subsequent skin grafting. Although grafted skin becomes revascularized, it remains unclear whether this vascular bed contributes to the control of internal temperature through neurally mediated cutaneous vasodilation and constriction. Evidence of impaired temperature control in burned/grafted skin has been suggested given findings that individuals with burns over 40 percent of their body have higher rectal temperatures during a thermal challenge relative to non-burned subjects. However, the presence or absence of skin grafting, as well as the maturity of the graft, was not controlled in those studies. Given the lack of information regarding the short and long term consequences of skin grafting on autonomic control of grafted skin, the primary objective of this proposal is to test the hypothesis that neural control of skin blood flow in human split-thickness grafts is initially impaired, but returns towards normal as the graft matures. These objectives will be accomplished by performing novel experiments to assess neural control of skin blood flow from subjects who had split-thickness skin grafts 5-9, 26-38, 50-62, and 72-86 months prior to testing. The information gained from the proposed studies will be valuable in understanding the short and long-term ramifications of this surgical procedure. Moreover, this information will provide a valuable benchmark from which physiological responses as a result of emerging technologies (i.e. synthetic skin, cultured skin, growth factors, etc.) could be compared, to identify if those technologies are beneficial to the patient with respect to reinnervation and revascularization of the grafted skin.
