title: Human cardiac valve interstitial cells in collagen sponge: a biological three-dimensional matrix for tissue engineering.
abstract: OBJECTIVE
  The use of a biological, biodegradable scaffold remodeled by cells to resemble a valve leaflet is an attractive approach to tissue engineering. The study aim was to evaluate the suitability of a three-dimensional biodegradable collagen sponge for maintenance of cell viability, proliferation and phenotype of cultured human cardiac valve interstitial cells (ICs).
  
  
  METHODS
  Pieces of valve leaflets were snap-frozen, sectioned and stained by immunoperoxidase. Interstitial cells were cultured from cardiac valves and plated onto glass coverslips or seeded in collagen sponge, then stained by immunofluorescence or immunoperoxidase. A panel of antibodies was used to determine cell phenotype. Cell viability was assessed using a dye-based cell proliferation assay, and cell death by lactate dehydrogenase measurement.
  
  
  RESULTS
  ICs variably expressing the phenotypic markers were found throughout the native valve leaflet, but particularly on the ventricular side. Cultured ICs either on coverslips or in collagen sponge expressed vimentin, a fibroblast surface antigen and variable amounts of smooth muscle (SM) alpha-actin. Expression of the other phenotypic markers, SM myosin, desmin and prolyl 4-hydroxylase differed: interestingly, the ratio of cells in collagen sponge expressing these markers reflected that found in the native valve leaflet. Confocal microscopy of ICs in the collagen sponge revealed the presence of cells with long interconnecting extensions indicating cell communication. Cell proliferation and cell death assays established that cells were not only viable after four weeks in the sponge, but were also proliferating.
  
  
  CONCLUSIONS
  This study demonstrates that collagen sponge is a suitable biodegradable scaffold that can maintain viable valve ICs and appears to enhance the capacity of the cell to express its original phenotype.
authors.affiliation: Division of Cardiothoracic Surgery, National Heart and Lung Institute, Faculty of Medicine, Imperial College of Science, Technology and Medicine at Harefield Hospital, Heart Science Centre, UK.
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Taylor
authors.forename: Sean P
authors.initials: SP
authors.lastname: Allen
authors.forename: Sally A
authors.initials: SA
authors.lastname: Dreger
authors.forename: Magdi H
authors.initials: MH
authors.lastname: Yacoub
mesh_terms: D001688:Biological Products / Q000502:physiology / Q000627:therapeutic use / Q000633:toxicity; D001705:Bioprosthesis; D002455:Cell Division / Q000187:drug effects* / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects* / Q000502:physiology*; D002478:Cells, Cultured; D003094:Collagen / Q000502:physiology / Q000627:therapeutic use* / Q000633:toxicity; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D006349:Heart Valve Diseases / Q000628:therapy; D006350:Heart Valve Prosthesis; D006351:Heart Valves / Q000166:cytology* / Q000378:metabolism / Q000637:transplantation; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D010641:Phenotype; D011474:Prosthesis Design; D023822:Tissue Engineering
chemical_list: D001688:Biological Products; D003094:Collagen