title: Acellular dermal matrix-based gene therapy augments graft incorporation.
abstract: BACKGROUND
  Acellular dermal matrix (ADM) is widely used for structural or dermal replacement purposes. Given its innate biocompatibility and its potential to vascularize, we explored the possibility of ADM to function as a small interfering RNA (siRNA) delivery system. Specifically, we sought to improve ADM vascularization by siRNA-mediated inhibition of prolyl hydroxylase domain-2 (PHD2), a cytoplasmic protein that regulates hypoxia inducible factor-1α, and improve neovascularization.
  
  
  METHODS
  Fluorescently labeled siRNA was used to rehydrate thin implantable ADM. Pharmacokinetic release of siRNA was determined. Twelve millimeter sections of ADM reconstituted with PHD2 siRNA (nonsense siRNA as control) and applied to dorsal wounds of 40 FVB mice. Grafts were sewn in, bolstered, and covered with occlusive dressings. Photographs were taken at 0, 7, and 14 d. Wounds were harvested at 7 and 14 d and analyzed (messenger RNA, protein, histology, and immunohistochemistry).
  
  
  RESULTS
  Release kinetics was first-order with 80% release by 12 h. By day 14, PHD2-containing ADM appeared viable and adherent, whereas controls appeared nonviable and nonadherent. Real-time reverse transcription-polymerase chain reaction demonstrated near-complete knockdown of PHD2, whereas vascular endothelial growth factor and FGF-2 were increased 2.3- and 4.7-fold. On enzyme-linked immunosorbent assay, vascular endothelial growth factor was increased more than fourfold and stromal cell-derived factor doubled. Histology demonstrated improved graft incorporation in treated groups. Immunohistochemical demonstrated increased vascularity measured by CD31 staining and increased new cell proliferation by denser proliferating cell nuclear antigen staining in treated versus controls.
  
  
  CONCLUSIONS
  We concluded that ADM is an effective matrix for local delivery of siRNA. Strategies to improve the matrix and/or genetically alter the local tissue environment can be envisioned.
authors: The Institute of Reconstructive Plastic Surgery, New York University Langone Medical Center, New York, New York.
authors: Meredith T
authors: MT
authors: Vandegrift
authors: The Institute of Reconstructive Plastic Surgery, New York University Langone Medical Center, New York, New York.
authors: Caroline
authors: C
authors: Szpalski
authors: The Institute of Reconstructive Plastic Surgery, New York University Langone Medical Center, New York, New York.
authors: Denis
authors: D
authors: Knobel
authors: The Institute of Reconstructive Plastic Surgery, New York University Langone Medical Center, New York, New York.
authors: Andrew
authors: A
authors: Weinstein
authors: The Institute of Reconstructive Plastic Surgery, New York University Langone Medical Center, New York, New York.
authors: Maria
authors: M
authors: Ham
authors: The Institute of Reconstructive Plastic Surgery, New York University Langone Medical Center, New York, New York.
authors: Obinna
authors: O
authors: Ezeamuzie
authors: The Institute of Reconstructive Plastic Surgery, New York University Langone Medical Center, New York, New York.
authors: Stephen M
authors: SM
authors: Warren
authors: The Institute of Reconstructive Plastic Surgery, New York University Langone Medical Center, New York, New York. Electronic address: pierre.saadeh@med.nyu.edu.
authors: Pierre B
authors: PB
authors: Saadeh
mesh_terms: D062088:Acellular Dermis; D000818:Animals; D055785:Gene Knockdown Techniques; D015316:Genetic Therapy; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases / Q000037:antagonists & inhibitors; D008297:Male; D051379:Mice; D018919:Neovascularization, Physiologic; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D016038:Skin Transplantation
chemical_list: D034741:RNA, Small Interfering; C490189:Egln1 protein, mouse; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases
keywords: Acellular dermal matrix; Alloderm; Graft incorporation; Graft vascularity; PHD2; Wound healing; siRNA