title: Pre-clinical evaluation of liposomal gene transfer to improve dermal and epidermal regeneration.
abstract: Liposomal gene transfer effectively enhances dermal and epidermal regeneration in burned rodents. To advance this treatment to clinical studies, we investigated the efficacy of liposomal gene transfer in a clinically relevant porcine wound model. Mimicking the clinical scenario, six female Yorkshire pigs (40-50 kg) received up to 12 burns of 50 cm(2) area that were fully excised and covered with skin autograft meshed at 4:1 ratio 24 h post-burn. Animals received control injections (empty liposomes), liposomes (DMRIE-C) containing 1 mg LacZ-cDNA, or liposomes (DMRIE-C) with 1 mg of platelet-derived growth factor (PDGF)-cDNA, or the naked PDGF gene. Serial biopsies were taken from different wound sites at multiple time points up to 12 days post-wounding. Transfection efficacy and transfection rate of LacZ and localization of beta-gal were determined by immunohistochemical and immunofluorescent techniques. RT-PCR and multiplex protein analysis (ELISA) were used to measure levels of growth factor mRNA transcribed and growth factor protein translated. Wound re-epithelialization and graft adhesion was evaluated using planimetric analysis and clinical scores. We found that peak transfection of liposomal beta-galactosidase occurred on day 2, with a fluorescence increase of 154% to baseline (P<0.001). Transfection intensity dropped to 115% above baseline on day 4 (P<0.001) and 109% on day 7. Immunohistochemistry showed a maximum transfection rate of 34% of cells in wound tissue. Gene transfer of liposomal PDGF-cDNA resulted in increased PDGF-mRNA and protein expression on days 2 and 4, and accelerated wound re-epithlialization as well as graft adhesion on day 9 (P<0.05). In this study, we showed that liposomal cDNA gene transfer is possible in a porcine wound model, and by using PDGF-cDNA we further showed that dermal and epidermal regeneration can be improved. These data indicate that liposomal gene transfer can be a new therapeutic approach to improve wound healing in humans.
authors.affiliation: Shriners Hospitals for Children and University of Texas Medical Branch, Galveston, TX 77550, USA.
authors.forename: L K
authors.initials: LK
authors.lastname: Branski
authors.forename: O E
authors.initials: OE
authors.lastname: Masters
authors.forename: D N
authors.initials: DN
authors.lastname: Herndon
authors.forename: R
authors.initials: R
authors.lastname: Mittermayr
authors.forename: H
authors.initials: H
authors.lastname: Redl
authors.forename: D L
authors.initials: DL
authors.lastname: Traber
authors.forename: R A
authors.initials: RA
authors.lastname: Cox
authors.forename: K
authors.initials: K
authors.lastname: Kita
authors.forename: M G
authors.initials: MG
authors.lastname: Jeschke
mesh_terms: D000818:Animals; D002056:Burns / Q000628:therapy*; D004817:Epidermis; D005260:Female; D018014:Gene Transfer Techniques; D008081:Liposomes; D023421:Models, Animal; D010982:Platelet-Derived Growth Factor / Q000235:genetics*; D012038:Regeneration; D012867:Skin / Q000293:injuries*; D016038:Skin Transplantation / Q000379:methods*; D013552:Swine; D014162:Transfection; D014945:Wound Healing / Q000235:genetics
chemical_list: D008081:Liposomes; D010982:Platelet-Derived Growth Factor