title: Human umbilical cord cells for cardiovascular tissue engineering: a comparative study.
abstract: OBJECTIVE
  Tissue engineering of viable, autologous cardiovascular replacements with the potential to grow, repair and remodel represents an attractive approach to overcome the shortcomings of available replacements for the repair of congenital cardiac defects. Currently, vascular myofibroblast cells represent an established cell source for cardiovascular tissue engineering. Cell isolation requires the invasive harvesting of venous or arterial vessel segments prior to scaffold seeding, a technique which may not be preferable, especially in pediatric patients. This study evaluates cells isolated from human umbilical cord artery, umbilical cord vein and whole cord as alternative autologous cell sources for cardiovascular tissue engineering.
  
  
  METHODS
  Cells were isolated from human umbilical cord artery (UCA), umbilical cord vein (UCV), whole umbilical cord (UCC) and saphenous vein segments (VC), and were expanded in culture. All three expanded cell groups were seeded on bioabsorbable copolymer strips and grown in vitro for 28 days. Isolated cells were characterized by flow cytometry, histology, immunohistochemistry, proliferation assays and compared to VC. Morphological analysis of the seeded polymer strips included histology, immunohistochemistry, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and uniaxial stress testing.
  
  
  RESULTS
  UCA, UCV and UCC demonstrated excellent cell growth properties comparable to VC. Following isolation, all three cell groups showed myofibroblast-like morphology and characteristics by staining positive for alpha-smooth muscle actin (ASMA) and vimentin. Histology and immunohistochemistry of seeded polymers showed good tissue and extracellular matrix formation containing collagen I, III and elastin. TEM showed viable myofibroblasts and the deposition of collagen fibrils and progressive growing tissue formation, with a confluent surface, was observed in SEM. No difference was found among the mechanical properties of UCA, UCV, UCC and VC tissue engineered constructs.
  
  
  CONCLUSIONS
  Tissue engineering of cardiovascular constructs by using UCA, UCV and UCC is feasible in an in vitro environment. Cell growth, morphology, characteristics and tissue formation were comparable between UCA, UCV, UCC and VC. UCC represent an attractive, readily available autologous cell source for cardiovascular tissue engineering offering the additional benefits of utilizing juvenile cells and avoiding the invasive harvesting of intact vascular structures.
authors.affiliation: Clinic for Cardiovascular Surgery, University Hospital, Raemistrasse 100, CH 8091 Zurich, Switzerland. a.kadner@web.de
authors.forename: Alexander
authors.initials: A
authors.lastname: Kadner
authors.forename: Gregor
authors.initials: G
authors.lastname: Zund
authors.forename: Christine
authors.initials: C
authors.lastname: Maurus
authors.forename: Christian
authors.initials: C
authors.lastname: Breymann
authors.forename: Sidika
authors.initials: S
authors.lastname: Yakarisik
authors.forename: Gregor
authors.initials: G
authors.lastname: Kadner
authors.forename: Marko
authors.initials: M
authors.lastname: Turina
authors.forename: Simon P
authors.initials: SP
authors.lastname: Hoerstrup
mesh_terms: D020341:Absorbable Implants; D001696:Biomechanical Phenomena; D002448:Cell Adhesion; D002455:Cell Division; D002478:Cells, Cultured; D005434:Flow Cytometry; D006330:Heart Defects, Congenital / Q000601:surgery*; D006801:Humans; D016130:Immunophenotyping; D008855:Microscopy, Electron, Scanning; D012501:Saphenous Vein / Q000166:cytology; D023822:Tissue Engineering / Q000379:methods*; D014469:Umbilical Arteries / Q000648:ultrastructure; D014470:Umbilical Cord / Q000648:ultrastructure*; D014471:Umbilical Veins / Q000648:ultrastructure