Adeno-associated viral vector-mediated human vascular endothelial growth factor gene transfer stimulates angiogenesis and wound healing in the genetically diabetic mouse

Abstract

Aims/hypothesis. We studied the gene therapy efficacy of diabetes-associated wound healing disorder with an adeno-associated virus (AAV) vector expressing the 165-amino acid isoform of human vascular endothelial growth factor-A (VEGF-A) by using an incisional skin-wound model produced on the back of female diabetic C57BL/KsJ db+/db+ mice and their normal littermates (db+/+m). Methods. Animals were randomized to receive intradermally into the wound edges either rAAV-LacZ (a control gene), or rAAV-VEGF165. Animals were killed on different days (7 and 14 days after skin injury) and wounded skin tissues were used for gene marker studies, histological evaluation and immunohistochemistry, and wound breaking strength analysis. Furthermore we studied the VEGF mature protein in the wounds. Results. We found that AAV vectors are highly efficient for gene transfer to the mouse skin, displaying an exquisite tropism for the panniculus carnosus by using the beta-galactosidase activity assay. We confirmed the increased expression of the angiogenic factor at day 7 by measuring the wound content of the mature protein. Delivery of VEGF165 to incisional skin wounds of diabetic mice resulted in a remarkable induction of new vessel formation with consequent improvement in the wound healing process. The rAAV-VEGF165 gene improved wound healing in diabetic mice through the stimulation of angiogenesis, reepithelization, synthesis and maturation of extracellular matrix. Moreover the recombinant AAV encoding the human VEGF165 increased the breaking strenght of the wound and enhanced the wound content of VEGF. Conclusion/interpretation. Our study suggests that VEGF gene transfer might represent a new approach to treat wound healing disorders associated with diabetes. [Diabetologia (2003) 46:546-555]

COMP-angiopoietin-1 promotes wound healing through enhanced angiogenesis, lymphangiogenesis, and blood flow in a diabetic mouse model

“…Therefore, restoring structural and functional microvasculature by supplementary delivery of VEGF-A or Ang1 could be beneficial to promote wound healing in diabetes. In fact, recent reports (12,13) indicate that topical application of VEGF-A promotes cutaneous wound healing through increased angiogenesis and by mobilizing and recruiting bone marrow-derived cells. However, exogenous VEGF-A often results in leaky, inflamed, and malformed vessels, greatly compromising its therapeutic utility (12)(13)(14).…”

“…In fact, recent reports (12,13) indicate that topical application of VEGF-A promotes cutaneous wound healing through increased angiogenesis and by mobilizing and recruiting bone marrow-derived cells. However, exogenous VEGF-A often results in leaky, inflamed, and malformed vessels, greatly compromising its therapeutic utility (12)(13)(14). In comparison, Ang1 is a specific growth factor functioning to generate a stable and functional vasculature through Tie2 and Tie1 receptors (14)(15)(16)(17)(18).…”

Regulation of scar formation by vascular endothelial growth factor

“…It is not surprising then, that many studies have found angiogenesis to be beneficial for wound repair. Stimulation of angiogenesis can enhance healing rates, [27][28][29][30][31][32][33] whereas a reduction in angiogenesis can impair the same. [34][35][36][37] The benefits of enhanced angiogenesis have primarily been shown in models of impaired wound healing 28,32,33 or severe injury.…”

“…Stimulation of angiogenesis can enhance healing rates, [27][28][29][30][31][32][33] whereas a reduction in angiogenesis can impair the same. [34][35][36][37] The benefits of enhanced angiogenesis have primarily been shown in models of impaired wound healing 28,32,33 or severe injury. [29][30][31] In contrast, several reports have shown that modulation of angiogenesis does not affect epidermal healing rates or overall wound closure to a great degree, [38][39][40][41][42][43] and some studies have even reported enhanced healing with reduced angiogenesis.…”

Discordant effects of a soluble VEGF receptor on wound healing and angiogenesis

“…Furthermore, it should be noted that adenoviral overexpression of VEGF isoforms (VEGF121 and VEGF165) or topical treatment with VEGF does accelerate wound healing, enhances wound vascularity and increases bursting strength of wounds in mice and rats. [31][32][33][34][35] The overall small impact of antiangiogenic therapy on wound healing may result from the fact that wound healing is a complex coordinated process encompassing a variety of different cell types (keratinocytes, endothelial cells, fibroblasts, inflammatory cells, epidermal cells) and growth factors other than VEGF such as basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), keratinocyte growth factor (KGF). Thus, despite an impairment of wound angiogenesis, redundant mechanisms not further analyzed in this study appear to prevent a gross delay in wound closure.…”