title: Living patches engineered from human umbilical cord derived fibroblasts and endothelial progenitor cells.
abstract: OBJECTIVE
  A major shortcoming in contemporary congenital heart surgery is the lack of viable replacement materials with the capacity of growth and regeneration. Here we focused on living autologous patches engineered from human umbilical cord derived fibroblasts and endothelial progenitor cells (EPCs) as a ready-to-use cell source for paediatric cardiovascular tissue engineering.
  
  
  METHODS
  EPCs were isolated from 20 ml fresh umbilical cord blood by density gradient centrifugation and myofibroblasts were harvested from umbilical cord tissue. Cells were differentiated and expanded in vitro using nutrient media containing growth factors. Before seeding, cell-phenotypes were assessed by immuno-histochemistry. Biodegradable patches fabricated from synthetic polymers (PGA/P4HB) were seeded with myofibroblasts followed by endothelialization with EPCs. All patches were cultured in a perfusion bioreactor. A subgroup of patches was additionally stimulated by cyclic strain. Analysis of the neo-tissues comprised histology, immuno-histochemistry, extracellular matrix (ECM) analysis and biomechanical testing.
  
  
  RESULTS
  Endothelial phenotypes of EPCs before seeding were confirmed by Ac-Dil-LDL, CD 31, von-Willebrand-Factor and eNOS staining. Histology of the seeded patches demonstrated layered viable tissue formation in all samples. The cells in the newly formed tissues expressed myofibroblast markers, such as desmin and alpha-SMA. The EPCs derived neo-endothelia showed constant endothelial phenotypes (CD 31, vWF). major constituents of ECM such as collagen and proteoglycans were biochemically detected. Stress-strain properties of the patches showed features of native-analogous tissues.
  
  
  CONCLUSIONS
  Living tissue engineered patches can be successfully generated from human umbilical cord derived myofibroblasts and EPCs. This new cell source may enable the tissue engineering of versatile, living, autologous replacement materials for congenital cardiac interventions.
authors.affiliation: Department of Surgical Research and Clinic for Cardiovascular Surgery, University Hospital and University of Zurich, Raemistrasse 100, CH 8091 Zurich, Switzerland.
authors.forename: Dörthe
authors.initials: D
authors.lastname: Schmidt
authors.forename: Anita
authors.initials: A
authors.lastname: Mol
authors.forename: Stefan
authors.initials: S
authors.lastname: Neuenschwander
authors.forename: Christian
authors.initials: C
authors.lastname: Breymann
authors.forename: Matthias
authors.initials: M
authors.lastname: Gössi
authors.forename: Gregor
authors.initials: G
authors.lastname: Zund
authors.forename: Marko
authors.initials: M
authors.lastname: Turina
authors.forename: Simon P
authors.initials: SP
authors.lastname: Hoerstrup
mesh_terms: D001672:Biocompatible Materials; D002454:Cell Differentiation; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology*; D004730:Endothelium, Vascular / Q000166:cytology*; D005347:Fibroblasts / Q000166:cytology; D006330:Heart Defects, Congenital / Q000601:surgery*; D006801:Humans; D016130:Immunophenotyping; D007231:Infant, Newborn; D009132:Muscles / Q000166:cytology*; D032446:Myoblasts / Q000166:cytology*; D013526:Surgical Mesh; D023822:Tissue Engineering / Q000379:methods*; D014470:Umbilical Cord / Q000166:cytology
chemical_list: D001672:Biocompatible Materials