Gene-enhanced tissue engineering: Applications for wound healing using cultured dermal fibroblasts transduced retrovirally with the PDGF-B gene

The treatment of difficult wounds remains a considerable clinical challenge . The goal of this study was Co determine whether genetic augmentation of d ermal cells on resorbable matrices can stimulate the healing process, leadi ng to increased tissue repair in a rat full-thickness excisional wound repa ir model. The human platelet-derived growth factor a (PDGF-B) gene was the initial gene chosen to test this hypothesis. The human PDGF-B gene was obta ined from human umbilical vein endothelial cells (HUVEC) by reverse transcr iptase-polymerase chain reaction, cloned into retroviral vectors under cont rol of either the cytomegalovirus promoter or the rat p-actin promoter, and introduced into primary rat dermal cells. In vitro results demonstrate tha t rat dermal cells are transduced and selected readily using retroviral vec tors, and engineered to secrete PDGF-B at a steady-state level of approxima tely 2 ng per milliliter culture per 1 million cells per 24 hours. Seeding of the gene-modified cells onto polyglycolic acid (PGA) scaffold matrices a nd introduction into the rat model resulted in substantially increased fibr oblast hypercellularity over control wounds at both 7 and 14 days posttreat ment. Our results demonstrate that gene augmentation of rat dermal fibrobla sts with the PDGF-B gene introduced into this animal model via PGA matrices modulates wound hearing and suggests that experimentation with additional genes for use separately or in combination with PDGF-B for additional, impr oved wound heating is warranted.