Autotransplantation of epithelial cells in the pig via an aerosol vehicle

A new method of delivery of epithelial suspensions with use of an aerosolization apparatus was examined in the pig. Full-thickness pig skin was harvested, and an epithelial suspension was created using standard techniques of dispase and trypsin. Twenty-four hours after skin harvest, four full-thickness wounds were created on the flanks of the pig. The control wound was sprayed with a solution without epithelial cells. The three experimental wounds were sprayed with epithelial cell suspensions (∼10 6 cells/suspension). Weekly evaluation with photographs, biopsies, and tracings were done for 4 weeks. At 10 weeks, the entire process was repeated with new wounds on the pig's back. Thirty-five wounds in five pigs were evaluated: 10 control (5 flank, 5 back) and 25 experimental (15 flank, 10 back). Control wounds healed by contraction alone, with epithelium at the edges only. After 4 weeks, an open area remained. Central epithelial islands developed in experimental wounds at 2 weeks. These islands coalesced to close the wounds by 4 weeks. Histology at 1 week showed groups of epithelial cells deeply embedded in granulation tissue. These groups became immature epithelial layers on the surface by 2 weeks, and all layers of epithelium were present by 4 weeks. Overall, flank experimental wounds epithelialized sooner, but contracted at the same rate as control wounds. In conclusion, epithelial cells can be delivered by an aerosolization apparatus and remain viable and proliferative in a pig model.