title: Optimizing recellularization of whole decellularized heart extracellular matrix.
abstract: BACKGROUND
  Perfusion decellularization of cadaveric hearts removes cells and generates a cell-free extracellular matrix scaffold containing acellular vascular conduits, which are theoretically sufficient to perfuse and support tissue-engineered heart constructs. However, after transplantation, these acellular vascular conduits clot, even with anti-coagulation. Here, our objective was to create a less thrombogenic scaffold and improve recellularized-left ventricular contractility by re-lining vascular conduits of a decellularized rat heart with rat aortic endothelial cells (RAECs).
  
  
  RESULTS
  We used three strategies to recellularize perfusion-decellularized rat heart vasculature with RAECs: retrograde aortic infusion, brachiocephalic artery (BA) infusion, or a combination of inferior vena cava (IVC) plus BA infusion. The re-endothelialized scaffolds were maintained under vascular flow in vitro for 7 days, and then cell morphology, location, and viability were examined. Thrombogenicity of the scaffold was assessed in vitro and in vivo. Both BA and IVC+BA cell delivery resulted in a whole heart distribution of RAECs that proliferated, retained an endothelial phenotype, and expressed endothelial nitric oxide synthase and von Willebrand factor. Infusing RAECs via the combination IVC+BA method increased scaffold cellularity and the number of vessels that were lined with endothelial cells; re-endothelialization by using BA or IVC+BA cell delivery significantly reduced in vitro thrombogenicity. In vivo, both acellular and re-endothelialized scaffolds recruited non-immune host cells into the organ parenchyma and vasculature. Finally, re-endothelialization before recellularization of the left ventricular wall with neonatal cardiac cells enhanced construct contractility.
  
  
  CONCLUSIONS
  This is the first study to re-endothelialize whole decellularized hearts throughout both arterial and venous beds and cavities by using arterial and venous delivery. The combination (IVC+BA) delivery strategy results in enhanced scaffold vessel re-endothelialization compared to single-route strategies. Re-endothelialization reduced scaffold thrombogencity and improved contractility of left ventricular-recellularized constructs. Thus, vessel and cavity re-endothelialization creates superior vascularized scaffolds for use in whole-organ recellularization applications.
authors.affiliation: Center for Cardiovascular Repair, University of Minnesota, Minneapolis, Minnesota, United States of America ; Department of Molecular Cardiology, Texas Heart Institute, Houston, Texas, United States of America.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Robertson
authors.affiliation: Medtronic, Mounds View, Minnesota, United States of America.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Dries-Devlin
authors.affiliation: Center for Cardiovascular Repair, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Stefan M
authors.initials: SM
authors.lastname: Kren
authors.affiliation: Department of Regenerative Medicine Research, Texas Heart Institute, Houston, Texas, United States of America.
authors.forename: Jana S
authors.initials: JS
authors.lastname: Burchfield
authors.affiliation: Center for Cardiovascular Repair, University of Minnesota, Minneapolis, Minnesota, United States of America ; Department of Regenerative Medicine Research, Texas Heart Institute, Houston, Texas, United States of America ; Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Doris A
authors.initials: DA
authors.lastname: Taylor
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D002102:Cadaver; D049109:Cell Proliferation; D002470:Cell Survival; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism / Q000637:transplantation; D005109:Extracellular Matrix / Q000378:metabolism*; D005260:Female; D006352:Heart Ventricles / Q000378:metabolism / Q000503:physiopathology; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D051381:Rats; D023822:Tissue Engineering; D054457:Tissue Scaffolds
chemical_list: C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III