title: Biocompatibility and recellularization potential of an acellular porcine heart valve matrix.
abstract: OBJECTIVE
  Tissue-engineered heart valves have the potential to overcome the limitations of present heart valve replacements. The study aim was to investigate the biocompatibility and recellularization potential of an acellular porcine valve matrix.
  
  
  METHODS
  Acellular porcine valve matrix contact and extract cytotoxicity was tested against porcine fibroblasts and smooth muscle cells (SMC). Porcine cells were incubated with decellularized aortic valve leaflets and aortic wall, and then assessed for changes in morphology and contact inhibition of growth. Soluble tissue extracts were prepared from decellularized leaflets and aortic wall, and assessed for their effect on the viability of cultured porcine cells. Acellular leaflets were seeded with either fibroblasts or SMC at 1 x 10(3) to 1 x 10(6) cells/cm2 for 24 h, or 5 x 10(4) cells/cm2 for 1-4 weeks. Cell attachment onto, and migration into, the acellular matrix was assessed by scanning electron microscopy and histology.
  
  
  RESULTS
  No contact inhibition of growth, or changes in fibroblast or SMC morphology, were observed following contact with the acellular valve matrix. No soluble extract cytotoxicity was found. Intermediate cell-seeding densities (2.5 x 10(4) to 7.5 x 10(4) cells/cm2) of both cell types produced confluent cell attachment; at the lowest concentration (1 x 10(3) cells/cm2) cell attachment was sparse, and at the highest (1 x 10(6) cells/cm2) it was multilayered. The SMC migrated throughout the leaflet matrix over four weeks, but there was no fibroblast migration into the matrix.
  
  
  CONCLUSIONS
  The absence of contact and extract cytotoxicity indicated that the acellular valve matrix was biocompatible in vitro. The failure of porcine fibroblasts to grow on, or infiltrate into, the matrix suggested that the SMC may be the preferred cell type for future leaflet recellularization studies in the development of a tissue-engineered heart valve replacement.
authors.affiliation: Institute of Medical and Biological Engineering, School of Biochemistry and Microbiology, University of Leeds, Leeds, UK. h.e.wilcox@bmb.leeds.ac.uk
authors.forename: Helen E
authors.initials: HE
authors.lastname: Wilcox
authors.forename: Sotiris A
authors.initials: SA
authors.lastname: Korossis
authors.forename: Catherine
authors.initials: C
authors.lastname: Booth
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Watterson
authors.forename: John N
authors.initials: JN
authors.lastname: Kearney
authors.forename: John
authors.initials: J
authors.lastname: Fisher
authors.forename: Eileen
authors.initials: E
authors.lastname: Ingham
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D002465:Cell Movement; D003584:Cytological Techniques; D006351:Heart Valves / Q000166:cytology*; D013552:Swine; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D001672:Biocompatible Materials