Cryopreservation of fetal skin is improved by extracellular trehalose

In this study, we tested a non-permeating cryoprotectant, trehalose, in combination with dimethyl sulfoxide (Me2SO) in the cryopreservation of human fetal skin and compared it to Me2SO and glycerol, protocols that are routinely used by skin banks. The viability of fetal skin from four groups (fresh, and cryopreserved with glycerol, Me2SO, or trehalose/Me2SO) were evaluated using an in vitro membrane integrity assay and by transplantation to immunodeficient mice. The membrane integrity assay showed a 90% integrity in fresh, unfrozen fetal skin. The number of intact cells dropped to 23 and 44% in fetal skin cryopreserved with glycerol and Me2SO, respectively. When trehalose was added to the cryopreservation medium containing Me2SO, the membrane integrity rose to 65%. When transplanted to immunodeficient mice, fetal skin cryopreserved with trehalose/Me2SO showed a graft performance indistinguishable from fresh unfrozen fetal skin and strikingly better graft take than that of fetal skin cryopreserved with Me2SO or glycerol only. These results suggest that cryopreservation protocols routinely used the skin banks can be improved by combining sugars such as trehalose with a permeating cryoprotectant. (C) 2002 Elsevier Science (USA). All rights reserved.