Development and Evaluation of a Thrombospondin 2 Deficient Pig as an Improved Source of Biomaterial

Project Summary Newinnovative biological materialsthat promote healing and prevent thrombosisare in high demand to improve a variety of extracellular matrixECMproducts ranging from wound dressings to vascular productsConsidering the aging population and a sharp rise in the incidence of diabetes and obesity worldwidethe increase in chronic wound treatment exacerbates this burdenIn the United States alonechronic wounds affect overmillion patients with annual costs exceedingbillionA second substantial market opportunity is to develop vascular conduits that resist thrombosis and remain patentThrombosis is the leading cause of failure in vascular graftsTraditional approaches to maintain graft patency involve delivery of anti platelet agents or coverage of the luminal surface by endothelial cells to minimize platelet activationMice deficient in thrombospondinTsphave a profound wound healing advantage and significantly reduced thrombosis in animal models of tissue or vascular graftThese unique properties of TSPnull ECM support its potential uses as a pro angiogenicnon thrombogenic treatment for wound therapies or in vascular applicationsWe propose to meet this need by production of TSPswine as a reliable source of TSPnull ECMCompared to rodentsswine have much greater geneticanatomicand physiological similarity to humansoffering an opportunity to produce vascular conduits that are of the correct size and non branching length for human vascular surgeriesWe hypothesize these animals will have enhanced wound healing characteristics and that biological scaffold materials derived from these animals will promote angiogenesisprovide elevated levels of growth and regulatory factorsand criticallyinhibit thrombosisWound treatment therapies produced from TSPnull and wild typeWTpig ECM will be assessed in WT pigs atmonths of age by histology and immunohistochemistry to quantify healing ratescell densityECM depositionvascularizationgrowth factorsand metalloproteinaseMMPdifferences of healing excisional skin woundsIn additiondecellularized ECM from both TSPand WT pigs will be prepared and evaluated in vitro for the ability to support fibroblast and endothelial cell interactions and inhibit platelet aggregationFinallysmall diameter arteries will be harvested from TSPand WT pigsdecellularized and analyzed for their abilities to reduce platelet aggregation in vitro and in vivo in a previously developed rat graft modelIf the role of TSPis conserved in swineTSPnull pigs will demonstrate increases in angiogenesislevels of vascular endothelial growth factorVEGFand MMPand MMPconcentrations in the ECMand reduced thrombosisThese factors will lead to far superior starting material for creation of decellularized biomaterials that will improve the quality of life for millions and have substantial market potential Project Narrative The acute shortage of human tissues for the use in surgical applications has prompted significant research into the use of animal tissue as a key alternative to meet these needsThe thrombospondinTSPpig that we propose to develop could revolutionize this initiative allowing for the development of new approaches for effective treatment of wounds in diabeticburn victimsor other high risk patients increasing healing rates and reducing instances of chronic woundsWe will also assess of the feasibility of using TSPpigs as a source for small caliber vascular conduit that resists thrombosisThis elusive medical device is consideredtheHoly Grailof vascular surgery