title: A novel small animal model of left ventricular tissue engineering.
abstract: BACKGROUND
  Complex congenital cardiac anomalies involving ventricular hypoplasia require either staged palliative reconstruction, converting the circulatory system to a single ventricle based pump, or allogeneic transplantation. Tissue engineering offers the potential for complete reconstruction of these defects, but is limited by the inability to model myocardial tissue engineering in a small animal. Our goal was to develop a small animal model for ventricular tissue engineering using rat heterotopic heart transplantation.
  
  
  METHODS
  Donor hearts were explanted after cardioplegic arrest and the left ventricular volume was augmented by the implantation of a biodegradable engineered construct. The heart was then transplanted heterotopically into syngeneic recipients creating either a volume loaded, functioning left ventricle, or a non-functioning left ventricle. Some of the engineered constructs were seeded with multipotent bone marrow-derived mesenchymal progenitor cells before implantation. Animals were evaluated by echocardiography, morphology, histology, and immunohistochemistry after 1 month.
  
  
  RESULTS
  A scaffolding constructed from polytetrafluoroethylene, polylactide mesh, and type I and IV collagen hydrogel resulted in minimal intracardiac inflammation without aneurysmal dilatation. Successful transplantation and differentiation of mesenchymal progenitor cells was accomplished using this scaffolding. No ventricular arrhythmias resulted from this surgical manipulation and echocardiography revealed both end systolic and diastolic volume augmentation with ventricular expansion.
  
  
  CONCLUSIONS
  We have developed an in vivo model of ventricular tissue engineering using heterotopic heart transplantation. Future work will focus on construction of ventricular tissue around pre-fabricated vascular networks in order increase cellular engraftment for ventricular reconstruction.
authors.affiliation: Department of Surgery, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Krupnick
authors.forename: Daniel
authors.initials: D
authors.lastname: Kreisel
authors.forename: Friederike H
authors.initials: FH
authors.lastname: Engels
authors.forename: Wilson Y
authors.initials: WY
authors.lastname: Szeto
authors.forename: Theodore
authors.initials: T
authors.lastname: Plappert
authors.forename: Sicco H
authors.initials: SH
authors.lastname: Popma
authors.forename: Alan W
authors.initials: AW
authors.lastname: Flake
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Rosengard
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000175:diagnosis; D001672:Biocompatible Materials / Q000627:therapeutic use; D001853:Bone Marrow / Q000187:drug effects / Q000601:surgery; D004195:Disease Models, Animal; D004452:Echocardiography; D004562:Electrocardiography; D016027:Heart Transplantation / Q000295:instrumentation; D006352:Heart Ventricles / Q000166:cytology / Q000000981:diagnostic imaging / Q000637:transplantation*; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D011091:Polyesters / Q000627:therapeutic use; D011100:Polyglycolic Acid / Q000627:therapeutic use; D019919:Prosthesis Implantation / Q000295:instrumentation; D051381:Rats; D011917:Rats, Inbred Lew; D013318:Stroke Volume / Q000502:physiology; D017154:Stromal Cells / Q000187:drug effects / Q000637:transplantation; D023822:Tissue Engineering; D016042:Transplantation, Heterotopic / Q000295:instrumentation
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011100:Polyglycolic Acid; C033616:poly(lactide)