In chronic wounds, numerous factors contribute to the diminished healing. Wound healing constituents, including heparan sulfate proteoglycans and numerous growth factors, are essential to normal skin wound healing. Several key growth factors such as FGF, VEGF, and PDGF require heparan sulfate-like polymers as co- receptors or co-activators for growth factor activity. Agenta Biotechnologies, Inc. has developed expertise and IP to generate heparan sulfate in situ, enabling secretion of a customized heparan sulfate polymer with a sulfation pattern specific for the wound environment. It is the objective of this project to develop a skin wound co-therapeutic that provides both a growth factor together with the critical co-stimulatory heparan sulfate proteoglycan to the healing wound for accelerated wound closure. Together with vascular endothelial growth factor, isoform 165 (VEGF165) we will deliver this co-therapeutic to full thickness excisional wounds on the dorsum of normal (Aim 1) and diabetic rats (Aim 2) via a chitosan dressing. Plasmid DNA expression constructs of the proteoglycan and the VEGF165 transgenes are characterized and ready for this proposed project. Alternatively, responses to replication-deficient adenovirus delivery of the co-therapeutic will be measured. The primary outcome measurement will be wound closure rates. Secondary outcome measurements of wound integrity include vascularization, collagen content, reepitheliazation, and granulation. Planned phase 2 work includes investigation of co-delivering FGF and PDGF with proteoglycan transgenes, as well as developing recombinant-based proteoglycan/growth factor therapeutics. Wound healing and tissue regeneration have begun a new era where the augmentation of bandages and dressings with key biological cell activators is showing success and gaining approval. Agenta Biotechnologies, Inc. has established themselves as leaders in manipulating proteoglycans for therapeutic use and is well-positioned to advance this novel therapeutic approach addressing the serious problem of impaired wound healing.
Upregulation of growth factors and heparan sulfate proteoglycans, especially those shown to be involved in wound healing, in the wound bed could enhance wound closure rates and wound integrity, especially needed for patients with impaired wound healing, such as diabetics. The first domain of perlecan, decorated with 3 heparan sulfate chains, and vascular endothelial growth factor, shown to be effective in wound healing are rational choices for this proposed co-therapeutic. This project will measure delivery dose, wound closure rates, and wound integrity in both normal and diabetic rat models.