Molecular Heparan Sulfate Delivery in Guided Tissue Regeneration

DESCRIPTION (provided by applicant): The role of proteoglycans and carbohydrate polymers such as heparan sulfate in biological processes are becoming better understood, but this new frontier has only begun to be explored. Tissue regeneration is also an emerging frontier. This proposed research, when completed, will make an important contribution to both the proteoglycan and tissue regenerative fields, with a specific, clinical impact on periodontal regeneration. Perlecan, originally named heparan sulfate proteoglycan-2, is now known to be an important component of all basement membranes (along with collagen type IV and laminin). There is strong scientific support and rationale for a role of heparan sulfate-decorated Perlecan in angiogenesis or neovascularization. The heparan sulfate of Perlecan is reported to promote cell adhesion, to promote proliferation and/or differentiation, and to bind and deliver growth factors. Expression of a heparan sulfate-decorated recombinant Perlecan D1 (rD1) in a variety of cell types has since been validated. The rD1 was shown to bind fibroblast growth factor and promoted cell adherence in vitro. In periodontal regeneration, barrier membranes are an important adjunct to procedures aimed at restoring the form and function of the mouth. During these guided tissue regenerative (GTR) procedures, barrier membranes are positioned between the surgical flap and the underlying regenerative site. Nevertheless, an unnecessarily high failure rate exists in GTR procedures due to failure of the flaps to heal with primary closure over the membranes and regenerative site, typically leading to exposure of the regenerative site to the oral environment. The objectives of this Phase I application are 1) to determine an effective manner of loading commonly used barrier membranes with Perlecan domain 1 expression constructs within clinically acceptable parameters, 2) to compare in vitro cellular expression of, and cellular responses to, the Perlecan domain 1 construct generated by membranes loaded with the Perlecan D1 transgene delivery system vs. the sham-loaded membranes, and 3) to compare in vivo responses generated by placement of the loaded vs. the sham-loaded surgical membranes in an animal model for healing by 2x intention. Membranes will be pre-treated by parameters established in vitro then secured beneath a gingival flap with a defined area of membrane exposure. Healing will be measured clinically and histologically where rate of exposed membrane coverage by epithelium will be the primary outcome. The well-supported rationale for heparan sulfate and Perlecan D1 delivery to support tissue regeneration, coupled with these preliminary data and Agenta's relevant patent, uniquely positions Agenta to fulfill the objectives of this proposed project.