e187 Reconstructive surgery applies several methods to cover acute or chronic wounds. Current options for coverage of skin defects include not only the stan- dard procedure, which is split- or full-thickness skin grafting, 1 but also the use of skin substitutes. 2 Prod- ucts currently applied and commercially available in clinical routine are acellular collagen dermal matrices (eg, Integra ® , Matriderm ® ) or epidermal substitutes (Epicel ® , Epibase ® ). Skin substitutes were extensively reviewed by Shevchenko et al 3 and most of them specifically lack properties of full-thickness skin, that is, color match, skin appendices, pliability, elasticity, and most of all mechanical stability. 4 It is obvious, that until today no successful full-thickness skin sub- stitute design has been achieved. The presently avail- able full-thickness constructs usually acquire only insufficient blood supply, leading to cell death in the substitute. Strategies to overcome this problem include prevascularization of skin substitutes, 5 bio- printing and electrospinning of biomaterials includ- ing application of defined growth factor cocktails, 6 and finally the use of stem cells. 7,8 All these strategies aim at speeding up the time until skin substitutes obtain sufficient blood supply and cellular composi- tion. In the clinical setting, surplus harvested skin Copyright © 2013 by the American Burn Association 1559-047X/2014 DOI: 10.1097/BCR.0b013e3182a226df Surplus harvested skin grafts are routinely stored at 4 to 6°C in saline for several days in plastic surgery. The purpose of this study was to evaluate the influence of storage on human skin graft performance in an in vivo intravital microscopic setting after transplantation. Freshly harvested human full-thickness skin grafts and split-thickness skin grafts (STSGs) after storage of 0, 3, or 7 days in moist saline at 4 to 6°C were transplanted into the modified dorsal skinfold chamber, and intravital microscopy was performed to evaluate vessel morphology and angiogenic change of the wound bed. The chamber tissue was harvested 10 days after transplantation for evaluation of tissue integrity and inflammation (hematoxylin and eosin) as well as for immunohistochemistry (human CD31, murine CD31, Ki67, Tdt-mediated dUTP-biotin nick-end labelling). Intravital microscopy results showed no differences in the host angiogenic response between fresh and preserved grafts. However, STSGs and full-thickness skin grafts exhibited a trend toward different timing and strength in capillary widening and capillary bud formation. Preservation had no influence on graft quality before transplantation, but fresh STSGs showed better quality 10 days after transplantation than 7-day preserved grafts. Proliferation and apoptosis as well as host capillary in-growth and graft capillary degeneration were equal in all groups. These results indicate that cells may activate protective mechanisms under cold conditions, allowing them to maintain function and morphology. However, rewarming may disclose underlying tissue damage. These findings could be translated to a new approach for the design of full-thickness skin substitutes. (J Burn Care Res 2014;35:e187–e196) From the *Division of Plastic and Reconstructive Surgery, Depart- ment of Surgery, University Hospital Zurich, Switzerland; †Division of Dermatology, University Hospital Zurich, Switzer- land; ‡Clinic for Cardiovascular Surgery, University Hospital Zurich, Switzerland; and §Institute for Experimental Surgery, University of Rostock, Germany. This study was financially supported by the Swiss National Science Foundation (SNF-Grant 310030_127366). Address correspondence to Nicole Lindenblatt, MD, Division of Plastic and Reconstructive Surgery, Department of Surgery, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland. In Vivo Evaluation of Wound Bed Reaction and Graft Performance After Cold Skin Graft Storage: New Targets for Skin Tissue Engineering Alicia Knapik, MSc,* Kai Kornmann,* Katrin Kerl, MD,† Maurizio Calcagni, MD,* Christian A. Schmidt, MD, PhD,‡ Brigitte Vollmar, MD,§ Pietro Giovanoli, MD,* Nicole Lindenblatt, MD* ORIGINAL ARTICLE