Adenoviral-mediated gene transfer of insulin-like growth factor 1 enhances wound healing and induces angiogenesis

Swathi Balaji, Maria Lesaint, Sukanta S. Bhattacharya, Chad Moles, Yashu Dhamija, Mykia Kidd, Louis D. Le, Alice King, Aimen Shaaban, Timothy M. Crombleholme, Paul Bollyky, Sundeep G. Keswani*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

Background Chronic wounds are characterized by a wound healing and neovascularization deficit. Strategies to increase neovascularization can significantly improve chronic wound healing. Insulin-like growth factor (IGF)-1 is reported to be a keratinocyte mitogen and is believed to induce angiogenesis via a vascular endothelial growth factor (VEGF)-dependent pathway. Using a novel ex vivo human dermal wound model and a diabetic-impaired wound healing murine model, we hypothesized that adenoviral overexpression of IGF-1 (Ad-IGF-1) will enhance wound healing and induce angiogenesis through a VEGF-dependent pathway. Methods Ex vivo: 6-mm full-thickness punch biopsies were obtained from normal human skin, and 3-mm full-thickness wounds were created at the center. Skin explants were maintained at air liquid interface. Db/db murine model: 8-mm full-thickness dorsal wounds in diabetic (db/db) mice were created. Treatment groups in both human ex vivo and in vivo db/db wound models include 1 × 108 particle forming units of Ad-IGF-1 or Ad-LacZ, and phosphate buffered saline (n = 4-5/group). Cytotoxicity (lactate dehydrogenase) was quantified at days 3, 5, and 7 for the human ex vivo wound model. Epithelial gap closure (hematoxylin and eosin; Trichrome), VEGF expression (enzyme-linked immunosorbent assay), and capillary density (CD 31 + CAPS/HPF) were analyzed at day 7. Results In the human ex vivo organ culture, the adenoviral vectors did not demonstrate any significant difference in cytotoxicity compared with phosphate buffered saline. Ad-IGF-1 overexpression significantly increases basal keratinocyte migration, with no significant effect on epithelial gap closure. There was a significant increase in capillary density in the Ad-IGF-1 wounds. However, there was no effect on VEGF levels in Ad-IGF-1 samples compared with controls. In db/db wounds, Ad-IGF-1 overexpression significantly improves epithelial gap closure and granulation tissue with a dense cellular infiltrate compared with controls. Ad-IGF-1 also increases capillary density, again with no significant difference in VEGF levels in the wounds compared with control treatments. Conclusions In two different models, our data demonstrate that adenoviral-mediated gene transfer of IGF-1 results in enhanced wound healing and induces angiogenesis via a VEGF-independent pathway. Understanding the underlying mechanisms of IGF-1 effects on angiogenesis may help produce novel therapeutics for chronic wounds or diseases characterized by a deficit in neovascularization.

Original languageEnglish (US)
Pages (from-to)367-377
Number of pages11
JournalJournal of Surgical Research
Volume190
Issue number1
DOIs
StatePublished - Jul 2014

Keywords

  • Diabetes
  • Gene therapy
  • IGF-1
  • Neovascularization
  • Organ culture
  • Wound healing
  • db/db

ASJC Scopus subject areas

  • Surgery

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