title: Bioactive porcine matrices in heart valve tissue engineering.
abstract: OBJECTIVE
  Platelet gel (PG), a storage vehicle of growth factors, can be considered for the application of growth factors in combination with mesenchymal stem cells (MSCs) to accelerate tissue regeneration. Moreover, the addition of bioactive factors to porcine aortic valves could result in a more rapid repopulation. The study aim was to load acellular porcine aortic valve matrices with the PG-rich growth factors and to evaluate the effect on MSC repopulation.
  
  
  METHODS
  Ovine mesenchymal stem cells (oMSCs) were isolated from sheep bone marrow. Acellular porcine heart valve matrices (n = 3) were preloaded with heparin and incubated with the PG for 2 h. A quantitative sandwich enzyme immunoassay was used to examine the release of basic fibroblast growth factor (bFGF) and transforming growth factor-beta (TGF-beta) from the matrices, oMSC repopulation was stimulated by static and dynamic culture.
  
  
  RESULTS
  The immunoassays revealed that heparin-preloaded PG-incubated matrices showed a sustained release of 56.28 pg/ml bFGF and 30.66 ng/ml TGF-beta1 after 24 h. Dynamic culture induced oMSC invasion in growth factor-loaded matrices. Cell density results showed that dynamic culture significantly enhanced the repopulation of growth factor-loaded matrices (75 +/- 21 cells/mm2) when compared to static culture (26 +/- 10 cells/mm2).
  
  
  CONCLUSIONS
  The incubation of a porcine aortic valve matrix with a PG concentrate creates a bioactive matrix. However, further fine-tuning of the PG concentration is necessary to take full advantage of platelet growth factor interaction between cells and the extracellular matrix in order to optimize cellular repopulation.
authors.affiliation: Department of Basic Medical Sciences, Ghent University, Ghent, Belgium.
authors.forename: Pamela
authors.initials: P
authors.lastname: Somers
authors.forename: Filip
authors.initials: F
authors.lastname: de Somer
authors.forename: Maria
authors.initials: M
authors.lastname: Cornelissen
authors.forename: Hubert
authors.initials: H
authors.lastname: Thierens
authors.forename: Guido
authors.initials: G
authors.lastname: Van Nooten
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000378:metabolism*; D001792:Blood Platelets / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism; D002452:Cell Count; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005109:Extracellular Matrix / Q000378:metabolism*; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D012756:Sheep; D013552:Swine; D023822:Tissue Engineering / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000378:metabolism*
chemical_list: D016212:Transforming Growth Factor beta; D016222:Fibroblast Growth Factor 2