title: Retention of an autologous endothelial layer on a bioprosthetic valve for the treatment of chronic deep venous insufficiency.
abstract: OBJECTIVE
  Percutaneous transcatheter implantation of porcine small intestinal submucosa (SIS) bioprosthetic valves has been reported as a treatment for chronic deep venous insufficiency (CDVI). Endothelial progenitor outgrowth cells (EOCs), isolated from whole ovine blood, were evaluated as a source of in vitro autologous seeding for SIS endothelialization. Retention of the EOC monolayer was evaluated to test the feasibility of delivering an endothelialized SIS valve.
  
  
  METHODS
  Twenty bioprosthetic venous valves were constructed from SIS sutured onto collapsible square stent frames and were seeded with ovine EOCs in vitro. Retention of the endothelial monolayer through valve loading and delivery (three valves), in vitro flow (three valves), and ex vivo flow (four valves) was evaluated with immunofluorescent staining and histologic analysis compared with paired unmanipulated control valves. In the ex vivo shunt loop, venous blood was pulled from an implanted dialysis catheter, through the valve, and returned to the sheep.
  
  
  RESULTS
  Immunofluorescent staining of EOCs on the valves after in vitro seeding revealed a confluent monolayer (95.6% ± 2.3% confluent) on each side of the valve. When examined by immunofluorescent staining, the endothelial monolayer remained intact after loading and delivery (97.1% ± 1.7%) and when subjected to flow in the in vitro loop (96.0% ± 3.0%). Histologic analysis of the valves subjected to the ex vivo shunt loop revealed retention of the endothelial monolayer.
  
  
  CONCLUSIONS
  Endothelial monolayers seeded on SIS were retained under loading and delivery, in vitro flow, and ex vivo flow. EOCs are a promising cell source for autologous endothelialization of bioprosthetic valves for the treatment of CDVI.
authors.affiliation: Department of Biomedical Engineering, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, L342, Portland, OR 97239, USA.
authors.forename: Casey M
authors.initials: CM
authors.lastname: Jones
authors.forename: Monica T
authors.initials: MT
authors.lastname: Hinds
authors.forename: Dusan
authors.initials: D
authors.lastname: Pavcnik
mesh_terms: D000818:Animals; D001705:Bioprosthesis; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation*; D002478:Cells, Cultured; D002908:Chronic Disease; D042783:Endothelial Cells / Q000637:transplantation*; D005240:Feasibility Studies; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007421:Intestine, Small / Q000637:transplantation*; D008422:Materials Testing; D008856:Microscopy, Fluorescence; D011474:Prosthesis Design; D012756:Sheep; D033581:Stem Cell Transplantation; D013552:Swine; D054457:Tissue Scaffolds; D014182:Transplantation, Autologous; D014689:Venous Insufficiency / Q000601:surgery*