Thursday, March 18, 2004 - 10:34 AM
5380

Pdgf-B but Not Fgf2 Plasmid Dna Improves Survival of Ischemic Myocutaneous Flaps

John Hijjawi, MD, Jon Mogford, PhD, Lois Chandler, PhD, Kevin Cross, MD, Hakim Said, MD, and Thomas Mustoe, MD.

HYPOTHESIS: Tissue flaps are commonly used for surgical reconstruction, especially over difficult wounds and in breast reconstruction. Complications due to inadequate flap perfusion are a source of morbidity, and in the lower extremity, can result in amputation. METHODS: We evaluated the ability of PDGF-B and FGF2 plasmid DNA, formulated in a Type I collagen matrix, to promote tissue survival in a rat transverse rectus abdominis muscle (TRAM) flap model based on the inferior deep epigastric artery. In the absence of any therapeutic, only ~24% of flap tissue survives in this model. The DNA/matrix formulations were delivered subcutaneously into the skin paddles 7 days prior to flap elevation, and tissues were harvested 7 days later. RESULTS: Our studies reveal dramatic increases in overall vascularity after treatment with both PDGF-B and FGF2 plasmid DNA; however, only PDGF-B increased flap survival (130% increase at 228 mg plasmid DNA/cm2 vs. controls; p<0.01). Transdermal spectral imaging demonstrated an increase in patent vessels supporting bloodflow in flaps treated with PDGF-B plasmid DNA versus the FGF2 transgene. CONCLUSIONS: Matrix-enabled gene therapy may therefore provide an effective, non-surgical approach to promote flap survival and is well suited for such surgical applications where transient therapeutic transgene expression is desired.