Gene-Enhanced Tissue Engineering

Abstract

The treatment of difficult wounds remains a considerable clinical challenge. The goal of this study was to determine whether genetic augmentation of dermal cells on resorbable matrices can stimulate the healing process, leading to increased tissue repair in a rat full-thickness excisional wound repair model. The human platelet-derived growth factor B (PDGF-B) gene was the initial gene chosen to test this hypothesis. The human PDGF-B gene was obtained from human umbilical vein endothelial cells (HUVEC) by reverse transcriptase-polymerase chain reaction, cloned into retroviral vectors under control of either the cytomegalovirus promoter or the rat beta-actin promoter, and introduced into primary rat dermal cells. In vitro results demonstrate that rat dermal cells are transduced and selected readily using retroviral vectors, and engineered to secrete PDGF-B at a steady-state level of approximately 2 ng per milliliter culture per 1 million cells per 24 hours. Seeding of the gene-modified cells onto polyglycolic acid (PGA) scaffold matrices and introduction into the rat model resulted in substantially increased fibroblast hypercellularity over control wounds at both 7 and 14 days posttreatment. Our results demonstrate that gene augmentation of rat dermal fibroblasts with the PDGF-B gene introduced into this animal model via PGA matrices modulates wound healing and suggests that experimentation with additional genes for use separately or in combination with PDGF-B for additional, improved wound healing is warranted.